WO2017107298A1 - 一种发送信道预约信号的方法和基站 - Google Patents

一种发送信道预约信号的方法和基站 Download PDF

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Publication number
WO2017107298A1
WO2017107298A1 PCT/CN2016/073701 CN2016073701W WO2017107298A1 WO 2017107298 A1 WO2017107298 A1 WO 2017107298A1 CN 2016073701 W CN2016073701 W CN 2016073701W WO 2017107298 A1 WO2017107298 A1 WO 2017107298A1
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WIPO (PCT)
Prior art keywords
signal
channel
base station
channel reservation
reservation signal
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PCT/CN2016/073701
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English (en)
French (fr)
Inventor
李汉涛
李振宇
韩金侠
马莎
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP16877112.9A priority Critical patent/EP3373484B1/en
Priority to JP2018532091A priority patent/JP6731484B2/ja
Priority to CN201680069828.XA priority patent/CN108292963B/zh
Priority to KR1020187018646A priority patent/KR102131676B1/ko
Publication of WO2017107298A1 publication Critical patent/WO2017107298A1/zh
Priority to US16/016,339 priority patent/US10735998B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
    • H04W28/26—Resource reservation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/14—Spectrum sharing arrangements between different networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0808—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0808—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
    • H04W74/0825—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA] with collision detection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/08—Access point devices

Definitions

  • the present invention relates to the field of communications technologies, and in particular, to a method and a base station for transmitting a channel reservation signal.
  • LAA unlicense-long term evolution
  • WiFi Wireless Fidelity
  • the network element in the LAA system includes a base station, and the network element in the WiFi system includes a WiFi access point (AP).
  • the base station uses a carrier sense/clear channel assessment (CS/CCA) mechanism to detect whether the current unlicensed channel is occupied.
  • CS/CCA carrier sense/clear channel assessment
  • the WiFi AP can only detect that the signal strength is greater than or equal to detection.
  • the detection threshold used for the signal is -82dBm
  • the detection threshold used to detect the LAA signal is -62dBm.
  • the WiFi AP will not be detected. Therefore, when the base station transmits the LAA signal with the signal strength between -82 dBm and -62 dBm on the unlicensed channel, the WiFi AP cannot effectively avoid the unlicensed channel, and eventually both may be caused by simultaneously transmitting signals on the unlicensed channel channel. Same frequency interference.
  • the base station may transmit a channel reservation signal on an unlicensed channel, wherein the channel reservation signal samples the WiFi frame format.
  • the WiFi AP will use the LAA system to which the base station belongs as the same system, thereby setting the detection threshold to -82 dBm, so that the LAA signal with a signal strength in the range of -82 dBm to -62 dBm can be detected, thereby enabling signal strength to be achieved.
  • the WiFi AP evades the unlicensed channel, thereby reducing the probability of occurrence of co-channel interference.
  • the base station transmits a channel reservation signal each time an unlicensed channel needs to be occupied, which causes waste of resources.
  • Embodiments of the present invention provide a method and a base station for transmitting a channel reservation signal to reduce waste of resources.
  • a method for transmitting a channel reservation signal including:
  • the base station detects whether a system signal is received on the unlicensed channel
  • the base station sends a channel reservation signal on the unlicensed channel to reserve the unlicensed channel.
  • the channel reservation signal is transmitted to reserve the unlicensed channel. Compared with the prior art, a certain amount of resources can be saved compared to transmitting a channel reservation signal each time an unlicensed channel needs to be occupied.
  • a second aspect provides a base station, including: a detecting unit and a sending unit;
  • the detecting unit is configured to detect whether a system signal is received on an unlicensed channel
  • the transmitting unit is configured to send a channel reservation signal on the unlicensed channel to reserve the unlicensed channel.
  • the base station in the embodiment of the present invention may be used to perform the method for transmitting a channel reservation signal according to the foregoing first aspect. Therefore, the technical effects that can be obtained by the base station may refer to the method for performing a channel reservation signal by the base station in the foregoing first aspect. The technical effects of the time are not repeated here.
  • the base station if the base station detects that the system signal is received on the unlicensed channel, the base station sends a channel reservation signal on the unlicensed channel to reserve an office.
  • the unlicensed channel may include: if the base station detects that the system signal is received on the unlicensed channel, the base station performs an idle channel detection CCA; if the detection result of the CCA is the unauthorized When the channel is idle, the base station transmits a channel reservation signal on the unlicensed channel to reserve the unlicensed channel.
  • the detecting unit may be further configured to: if it is detected that the system signal is received on the unlicensed channel, perform idle channel detection CCA;
  • the unit may be specifically configured to: if the detection result of the CCA is that the unlicensed channel is idle, send a channel reservation signal on the unlicensed channel to reserve the unlicensed channel.
  • the optional implementation can ensure that the unlicensed channel is idle when the base station transmits the channel reservation signal, and the channel reservation sent by the base station is compared with the prior art solution that does not perform any operation before the channel reservation signal is sent.
  • the probability that a signal is received by the same system or a different system in which the system signal is located increases, thereby increasing the probability of achieving the purpose of scheduling the channel and avoiding co-channel interference.
  • the detecting, by the base station, whether the system signal is received on the unlicensed channel may include: detecting, by the base station, whether to receive on the unlicensed channel in each detection period. a system signal; wherein the detection period includes one or more detection durations; in this case, if the base station detects that the system signal is received on the unlicensed channel, the base station performs CCA, Including: if stated When the base station detects that the system signal is received on the unlicensed channel within any one of the detection durations, the base station stops detecting the system signal within the detection period to which the detection duration belongs, and performs CCA.
  • the sending unit may be configured to: detect, during each detection period, whether a system signal is received on the unlicensed channel; wherein the detection period includes One or more detection durations.
  • the detecting unit may be configured to: if it is detected that the system signal is received on the unlicensed channel within any one of the detection durations, stop detecting in a detection period to which the detection duration belongs The system signals and performs CCA.
  • the optional implementation provides a detection period based on a large granularity and a detection duration of a small granularity.
  • the detection period of the large granularity can avoid the detection of missing system signals, and the detection duration of the small granularity enables the base station to quickly detect the system signal. .
  • the performing, by the base station, the CCA may include: in a Cell On/Off mechanism, the base station starts CCA in N subframes before the LAA system to which the base station belongs is in Cell On Wherein the duration of the N subframes is greater than or equal to the maximum duration of a data transmission of the system to which the system signal belongs.
  • the detecting unit when the detecting unit performs CCA, the detecting unit may be specifically configured to: in the Cell On/Off mechanism, before the LAA system to which the base station belongs is in Cell On The N subframes start CCA; wherein the duration of the N subframes is greater than or equal to the maximum duration of one data transmission of the system to which the system signal belongs.
  • the length of the Cell On and the length of the Cell Off are relatively fixed, so the cut-off point between Cell On and Cell Off is generally fixed.
  • This optional implementation changes the demarcation point between Cell On and Cell Off, specifically the time at which the base station transmits the channel reservation signal as a new demarcation point.
  • the time when the CAA detection result is that the channel is idle is taken as a new demarcation point.
  • the CCA satisfies at least one of the following conditions: condition 1, the detection threshold of the CCA is less than or equal to d Where d is the minimum value of the detection threshold when the base station performs CCA on the same system and the detection threshold when performing CCA on the different system.
  • condition 2 The detection duration of the CCA is greater than or equal to the maximum length of the detection time when the base station performs CCA on the same system and the detection duration when the CCA is performed on the different system.
  • Condition 3 The defer duration of the CCA is greater than or equal to the maximum value of the defer duration when the base station performs CCA on the same system and the defer duration when the CCA is performed on the different system.
  • This alternative implementation provides an enhanced CCA, ie, a CCA that reduces the detection threshold of the CCA and/or extends the detection duration.
  • the detection threshold of the CCA can be set low enough, so that the base station can detect the different system signal with smaller transmission power.
  • the base station can extend the detection duration of the CCA to improve the accuracy of the CCA detection by the base station.
  • the sending, by the base station, the channel reservation signal on the unlicensed channel may include: the base station continuously transmitting S channel reservation signals on the unlicensed channel.
  • the sending unit is specifically configured to: continuously send S channel reservation signals on the unlicensed channel.
  • the reserved field of the sth channel reservation signal is used to mark the sum of the duration occupied by the s+1th channel reservation signal to the Sth channel reservation signal and the length of time to be reserved; 1 ⁇ s ⁇ S, S and s are both integers, and the length of time to be reserved refers to the length of time required to transmit data on the unlicensed channel.
  • This optional implementation 1 can be based on a Cell On/Off mechanism or an LBT mechanism.
  • the optional embodiment can be understood as: when the detection result of the CCA is that the unlicensed channel is idle, a plurality of channel reservation signals are immediately transmitted; and, the channel reservation signal in this embodiment is independent of the OFDM symbol.
  • the sending, by the base station, the channel reservation signal on the unlicensed channel may include: the base station is on the unlicensed channel A channel reservation signal is transmitted on each target OFDM symbol.
  • the sending unit may be specifically configured to: send a channel reservation signal on each target orthogonal frequency division multiplexing (OFDM) symbol on the unlicensed channel.
  • OFDM orthogonal frequency division multiplexing
  • the target OFDM symbol refers to P OFDM symbols starting from the first OFDM symbol after the OFDM symbol at the target time, and the target time is that the detecting unit determines that the detection result of the CCA is the unlicensed channel.
  • P is an integer greater than or equal to 1.
  • the optional implementation manner 2 can be understood as: the first OFDM symbol after the OFDM symbol occupied by the CCA is invalid when the unlicensed channel is idle, and the channel reservation signal is sent by the OFDM symbol. Time unit.
  • the optional implementations 1, 2 and the base station in the prior art are in a fixed position of one subframe (for example, a subframe start boundary of one subframe or a third OFDM symbol after a subframe start boundary, etc.)
  • the detection result from the CCA caused by the base station transmitting the channel reservation signal at a fixed position in the prior art is the position of the fixed transmission channel reservation signal when the unlicensed channel is idle.
  • the problem that the unlicensed channel is preempted by the same system or different systems occurs, so that the LAA system where the base station is located can quickly make an appointment to the unlicensed channel.
  • S>1 that is, the base station transmits a plurality of channel reservation signals, it is possible to improve the reception success rate and the decoding success rate of the channel reservation signal by the receiver of the channel reservation signal.
  • the marking method of the reserved field of the channel reservation signal on the target OFDM symbol includes, but is not limited to, the following manners 1-3:
  • the reservation field of the channel reservation signal sent on the pth target OFDM symbol is used to mark the remaining duration of the pth target OFDM symbol occupied by the channel reservation signal; a reserved field of the channel reservation signal transmitted on the target OFDM symbol is used to mark the Pth target OFDM
  • Mode 2 A reserved field of each of the channel reservation signals sent on each of the target OFDM symbols is used to mark a sum of a remaining duration of the target OFDM symbol occupied by the channel reservation signal and a duration to be reserved.
  • Manner 3 The reserved field of the channel reservation signal sent on the mth target OFDM symbol is used to mark (Pm)* the sum of the duration of the OFDM symbol and the duration to be reserved; wherein, 1 ⁇ m ⁇ P, m is an integer .
  • the channel reservation signals on each target OFDM symbol on the modes 1, 2, and 3 all reserve the duration remaining after the channel reservation signal is occupied on the OFDM symbol, so that the unlicensed channel can be avoided in each target OFDM symbol.
  • the remaining time is preempted by the same system or different systems.
  • mode 2 does not need to be reserved according to the index of the OFDM symbol, and the implementation is simple.
  • Mode 3 can accurately reserve the length of time to be reserved by using any one of the target OFDM symbols. It should be noted that, in the specific implementation, in the case of no conflict, some of the features in modes 1, 2, and 3 may be combined according to actual needs to form a new method for marking the reserved field, and no longer one by one. List.
  • the padding information is further sent by the channel reservation signal on any one or more target OFDM symbols
  • the padding information may include, but is not limited to, any one of the following information 1) to 3): 1) a WiFi control frame; 2) a combination of a WiFi signal preamble and a signal signal field; 3) a WiFi signal preamble, A combination of signal signal field and invalid data.
  • the padding information may be before the target channel reservation signal (ie, the channel reservation signal described above) or after the target channel reservation signal; the target channel reservation signal may be represented by a WiFi control frame, or may be a WiFi signal preamble. Combined with the signal field.
  • the target The padding information in the OFDM symbol includes any one of a combination of a WiFi signal preamble and a signal field, or a combination of a WiFi signal preamble, a signal field, and invalid data
  • padding information in the target OFDM symbol is The channel reservation signal in the OFDM symbol is transmitted later, and the length field in the signal field is marked as 0. In this way, the receiver of the channel reservation signal is prevented from receiving and parsing the subsequent data according to the length field, thereby mistaking the complete channel reservation signal as LAA service data.
  • the padding information in the target OFDM symbol includes any one of the following: a combination of a WiFi signal preamble and a signal field, or a WiFi signal preamble, a signal field, and invalid data.
  • Combination, and padding information in the target OFDM symbol is transmitted before a channel reservation signal in the OFDM symbol, a length field in the signal field is marked as 0, or the signal preamble is on the target OFDM symbol And the remaining duration after the signal field is occupied.
  • the sending, by the base station, the channel reservation signal on the unlicensed channel may include: the base station is in the unauthorized The first channel reservation signal is transmitted on the channel, and after the preset time period, the second channel reservation signal is transmitted.
  • the sending unit may be configured to: send the first channel reservation signal on the unlicensed channel, And after the preset time period, the second channel reservation signal is transmitted.
  • the modulation order of the data transmitted on the subframe in which the second channel reservation signal is located is less than or equal to the modulation order of the data transmitted on the subframe reserved by the first channel reservation signal
  • the coding rate of the data transmitted on the subframe in which the reservation signal is located is less than or equal to the coding rate of the data transmitted on the subframe reserved by the first channel reservation signal.
  • the decoding success rate of the second channel reservation signal by the receiver of the channel reservation signal can be improved.
  • the method may further include: the base station sending a configuration message to the target terminal.
  • the sending unit is further configured to: send a configuration message to the target terminal.
  • the configuration message includes a number r of OFDM symbols carrying the channel reservation signal on the target subframe and a number R of OFDM symbols used to carry control data in the target subframe to indicate that the target terminal is located
  • the R+r+1 OFDM symbols of the target subframe start to receive/demodulate service data; wherein the target subframe is a subframe that carries the channel reservation signal, and both R and r are greater than or equal to 1. Integer.
  • the base station needs to send the number r of OFDM symbols carrying the channel reservation signal on the target subframe to the target terminal, to indicate that the base station uses r OFDM symbol bearer channel reservation signals, that is, from the R+r+
  • the target terminal needs to receive/parse the service data from the R+r+1 OFDM symbols.
  • the method may further include: The base station performs sampling rate conversion on the channel reservation signal to obtain a target signal, wherein the sampling rate of the target signal is a sampling rate of the LAA signal.
  • the sending, by the base station, the channel reservation signal on the unlicensed channel may include: the base station transmitting the target signal on the unlicensed channel.
  • the base station may further include: a converting unit, where the sending unit is in the unlicensed channel Before transmitting the channel reservation signal, the channel reservation signal is subjected to sampling rate conversion to obtain a target signal; wherein the sampling rate of the target signal is a sampling rate of the LAA signal.
  • the sending unit may be specifically configured to: send the target signal on the unlicensed channel.
  • the optional implementation manner can implement common hardware transmission of the LAA signal and the channel reservation signal, that is, the LAA signal and the channel reservation signal can be shared by time division multiplexing.
  • a set of RF links saves hardware resources and reduces costs.
  • the system signal is a WiFi signal; and the method may further include: the base station sending an RTS frame to the target terminal.
  • the system signal is a WiFi signal; and the sending unit is further configured to: send a request to the target terminal to send RTS frame.
  • the receiving media access control MAC address field of the RTS frame is used to mark a MAC address of a WiFi chip of the target terminal, so that the terminal broadcasts a clear CTS frame, where the CTS frame flag is used to indicate
  • the information of the time length to be reserved is further such that the device receiving the CTS frame does not transmit data within the time period to be reserved.
  • the optional implementation provides a mechanism for a base station to send an RTS frame to a target terminal; devices (including terminals, base stations, etc.) around the target terminal can receive CTS frames, and after receiving the CTS frame, the devices are waiting for a reservation.
  • the data is not transmitted within, so that the interference of the surrounding devices to the target terminal can be reduced; thereby improving the communication quality of communication between the base station and the target terminal in the LAA system.
  • the system signal is a WiFi signal; the duration to be reserved is T; and the maximum duration of the combination of the WiFi signal preamble and the signal field is reserved.
  • the maximum time reserved for the WiFi control frame is b.
  • the base station sends the channel reservation signal on the unlicensed channel, which may include, but is not limited to, any of the following situations:
  • the base station transmits a channel reservation signal represented by a combination of a set of WiFi signal preambles and a signal field on the unlicensed channel, or a channel reservation signal represented by a set of WiFi control frames.
  • the base station transmits a channel reservation signal represented by a combination of a plurality of sets of WiFi signal preambles and a signal field on the unlicensed channel, or a channel reservation signal represented by a set of WiFi control frames.
  • the base station transmits, on the unlicensed channel, a channel reservation signal represented by a combination of multiple sets of WiFi signal preambles and signal fields, or a channel reservation signal represented by multiple sets of WiFi control frames, or a group/multiple A channel reservation signal represented by a combination of a group of WiFi signal preambles and a signal field and a channel reservation signal represented by one or more sets of WiFi control frames.
  • the system signal is a WiFi signal; the time to be reserved is T; and the combination of the WiFi signal preamble and the signal field is reserved.
  • the maximum duration is a, and the maximum duration of the WiFi control frame reservation is b.
  • the sending unit is specifically used to:
  • a channel reservation signal represented by a combination of a set of WiFi signal preambles and a signal field is transmitted on the unlicensed channel, or a channel reservation signal represented by a set of WiFi control frames.
  • a channel reservation signal represented by a combination of a plurality of sets of WiFi signal preambles and signal fields, or a channel reservation signal represented by a set of WiFi control frames is transmitted on the unlicensed channel.
  • a channel reservation signal represented by a combination of a plurality of sets of WiFi signal preambles and signal fields, or a channel reservation signal represented by a plurality of sets of WiFi control frames, or one/multiple groups are transmitted on the unlicensed channel.
  • the sending, by the base station, the channel reservation signal on the unlicensed channel may include:
  • the base station transmits a channel reservation signal on one or more OFDM symbols before the LAA system to which it belongs is in Cell On; or
  • the base station transmits a channel reservation signal on one or more OFDM symbols starting from Cell On when the LAA system to which the LAA system to which it belongs is at Cell On; or
  • a base station transmits a channel reservation signal on an OFDM symbol of one or more data regions from which Cell On starts when its associated LAA system is in Cell On.
  • the sending unit may be specifically configured to:
  • the base station transmits a channel reservation signal on one or more OFDM symbols before the LAA system to which it belongs is in Cell On; or
  • the base station transmits a channel reservation signal on one or more OFDM symbols starting from Cell On when the LAA system to which the LAA system to which it belongs is at Cell On; or
  • a base station transmits a channel reservation signal on an OFDM symbol of one or more data regions from which Cell On starts when its associated LAA system is in Cell On.
  • This alternative embodiment can be applied to a scenario in which a channel reservation is performed by an LAA system that does not have a CCA function, that is, in an LAA system that does not have a CCA function, an unlicensed channel can be reserved.
  • the base station can directly reserve the unlicensed channel by using the optional embodiment without performing CCA without the high-throughput service of the same system or different systems.
  • the base station sends the channel reservation signal on the unlicensed channel, which may include: in the cross-carrier scheduling scenario, if the result of the CCA detection is an unlicensed channel When idle, the base station transmits a channel reservation signal on the last one or more OFDM symbols of the unlicensed channel for carrying control data.
  • the sending unit is specifically configured to: use the last one or more OFDM symbols for carrying the control data on the unlicensed channel.
  • the channel reservation signal is transmitted.
  • This alternative implementation effectively utilizes the resources of the control region of the unlicensed channel. Another In addition, it can improve spectral efficiency.
  • the base station sends a channel reservation signal on the unlicensed channel to reserve the unlicensed channel, including: if the detection result of the CCA is unauthorized When the channel is idle, and T1 ⁇ T2, the base station delays the duration of T1-T2 after the end of the CCA detection, and transmits a channel reservation signal on the unlicensed channel to reserve the unlicensed channel.
  • the sending unit is specifically configured to: if the detection result of the CCA is that the unlicensed channel is idle, and T1 ⁇ T2, delay the duration of T1-T2 after the end of the CCA detection, A channel reservation signal is transmitted on the unlicensed channel to reserve an unlicensed channel.
  • T1 is the delay of the uplink transmission of the LAA system to which the base station belongs to the downlink transmission
  • T2 is the time required for the base station to transmit the channel reservation signal to the air interface.
  • T1 is the delay of the uplink transmission of the LAA system to which the base station belongs to the downlink transmission
  • T2 is the time required for the base station to transmit the channel reservation signal to the air interface.
  • the base station sends a channel reservation signal on the unlicensed channel to reserve the unlicensed channel, including: if the detection result of the CCA is unauthorized When the channel is idle and T1 ⁇ T2, the base station transmits a channel reservation signal on the unlicensed channel to reserve an unlicensed channel.
  • the sending unit is specifically configured to: if the detection result of the CCA is that the unlicensed channel is idle, and T1 ⁇ T2, send a channel reservation signal on the unlicensed channel to reserve the unauthorized channel.
  • T1 is the delay from the uplink transmission to the downlink transmission of the LAA system to which the base station belongs, and is the time required for the base station to transmit the channel reservation signal to the air interface. In this way, other systems can be prevented from preempting the unlicensed channel.
  • a third aspect provides a base station, including: a processor, a memory, and a system bus; the memory is configured to store a computer to execute an instruction, and the processor is connected to the memory through the system bus, when the base station is running The processor executing the memory The stored computer executes instructions to cause the base station to perform any of the methods of transmitting the channel reservation signal provided by the first aspect or any alternative implementation of the first aspect.
  • the base station in the embodiment of the present invention may be used to perform the method for transmitting a channel reservation signal according to the foregoing first aspect. Therefore, the technical effects that can be obtained by the base station may refer to the method for performing a channel reservation signal by the base station in the foregoing first aspect. The technical effects of the time are not repeated here.
  • a readable medium comprising computer-executable instructions, wherein when the processor of the base station executes the computer to execute an instruction, the base station performs the method of transmitting a channel reservation signal.
  • the readable medium provided by the embodiment of the present invention can perform the foregoing method for transmitting a channel reservation signal. Therefore, the technical effects that can be obtained can be referred to the embodiment of the foregoing method, and details are not described herein again.
  • a system for transmitting a channel reservation signal comprising a base station and a plurality of terminals, the base station being the base station described in the second aspect or the optional implementation of any of the second aspects.
  • the system for transmitting a channel reservation signal includes the base station described in the second aspect or the optional method of the second aspect, and the technical effects thereof can be referred to the embodiment of the base station. , will not repeat them here.
  • FIG. 1 is a schematic structural diagram of a system in which a LAA system and a WiFi system coexist in a technical solution provided by an embodiment of the present invention
  • FIG. 2 is a schematic diagram of a WiFi physical frame structure
  • FIG. 3 is a schematic diagram of an RTS frame structure
  • FIG. 4 is a schematic diagram of a CTS frame structure
  • FIG. 5 is a flowchart of a method for transmitting a channel reservation signal according to an embodiment of the present invention
  • FIG. 6 is a schematic diagram 1 of a transmission channel reservation signal according to an embodiment of the present invention.
  • 6(a) is a schematic diagram of a transmission channel reservation signal according to an embodiment of the present invention.
  • FIG. 6(b) is a schematic diagram of another transmission channel reservation signal according to an embodiment of the present invention.
  • FIG. 7 is a schematic diagram of a relationship between a detection period P and a detection duration T according to an embodiment of the present invention.
  • FIG. 8 is a schematic diagram of a method for triggering a CCA according to an embodiment of the present invention.
  • FIG. 9 is a second schematic diagram of a transmission channel reservation signal according to an embodiment of the present invention.
  • FIG. 10 is a schematic diagram 3 of a transmission channel reservation signal according to an embodiment of the present invention.
  • FIG. 11 is a schematic diagram 4 of a transmission channel reservation signal according to an embodiment of the present invention.
  • FIG. 12 is a schematic diagram 1 of determining a target OFDM symbol according to an embodiment of the present invention.
  • FIG. 13 is a schematic diagram 2 of determining a target OFDM symbol according to an embodiment of the present disclosure
  • FIG. 14 is a schematic diagram 3 of determining a target OFDM symbol according to an embodiment of the present disclosure.
  • FIG. 15 is a schematic diagram 4 of determining a target OFDM symbol according to an embodiment of the present disclosure.
  • FIG. 16 is a first schematic diagram of a method for marking a reserved field according to an embodiment of the present invention.
  • FIG. 17 is a second schematic diagram of a method for marking a reserved field according to an embodiment of the present invention.
  • FIG. 18 is a third schematic diagram of a method for marking a reserved field according to an embodiment of the present invention.
  • FIG. 19 is a first schematic diagram of a method for filling a remaining duration according to an embodiment of the present invention.
  • 20 is a second schematic diagram of a method for filling a remaining duration according to an embodiment of the present invention.
  • FIG. 21 is a schematic diagram 5 of a transmission channel reservation signal according to an embodiment of the present disclosure.
  • FIG. 22 is a schematic structural diagram 1 of a base station according to an embodiment of the present disclosure.
  • FIG. 23 is a schematic structural diagram 2 of a base station according to an embodiment of the present disclosure.
  • FIG. 24 is a schematic structural diagram 3 of a base station according to an embodiment of the present invention.
  • the executor of the technical solution provided by the embodiment of the present invention is a base station. Therefore, the same system and the different system described in the embodiments of the present invention are described with reference to the LAA system to which the base station belongs; and the “same system” And “different systems” refer to systems that are capable of communicating with terminals using unlicensed channels.
  • the same system refers to the LAA system; the different system refers to the non-LAA system, and may be, for example, a WiFi system, a radio positioning system, or the like.
  • one LAA system is different from the same system as two LAA systems.
  • the terminal may be a user equipment (UE) in the LAA system, or a station (station, STA) in the WiFi system.
  • UE user equipment
  • STA station
  • the same system signal refers to a signal sent by the same system that conforms to the same system frame format, for example, the LAA signal sent by the LAA system, specifically the LAA signal sent by the base station in the LAA system.
  • the different system signal refers to a signal sent by the different system conforming to the format of the different system frame, for example, a WiFi signal sent by the WiFi system, specifically a WiFi AP sent by the WiFi system or a WiFi signal sent by the WiFi STA.
  • the same system may also send a signal conforming to a certain system frame format.
  • the LAA system may send a channel reservation signal, specifically, the base station in the LAA system transmits a channel reservation signal, where the channel reservation signal conforms to the WiFi frame. format.
  • the WiFi signal can be transmitted; however, for distinguishing, the WiFi signal hereinafter refers to the WiFi signal transmitted by the WiFi system unless otherwise specified;
  • the WiFi signal transmitted by the LAA system is directly represented by a channel reservation signal.
  • WiFi data refers to data transmitted by the WiFi system to the terminal; WiFi control data and WiFi service data, etc.
  • the LAA data refers to data transmitted by the LAA system to the terminal; specifically, it may include LAA control data (for example, channel reservation signal) and LAA service data.
  • LAA control data for example, channel reservation signal
  • LAA service data for example, channel reservation signal
  • first and second and the like in this application are used to distinguish different objects, rather than to describe a particular order of the objects.
  • the first channel reservation signal and the second channel reservation signal are used to distinguish different channel reservation signals, rather than to describe a particular order of channel reservation signals.
  • WIFI APs refer to two or more WIFI APs.
  • system and network in this application have the same meaning and are used interchangeably.
  • A/B can be understood as A or B.
  • the technical solution provided by the embodiment of the present invention can be applied to a scenario in which the LAA system coexists with the same system or a different system.
  • the scenario in which the LAA system and the WiFi system coexist is taken as an example for description.
  • the network element related to the embodiment of the present invention involved in the LAA system includes a base station, and the network element related to the embodiment of the present invention involved in the WiFi system includes a WIFI AP.
  • the LAA system or the WiFi system in the embodiment of the present invention further includes a terminal, where the terminal can be connected to the base station or the WIFI AP to communicate with the base station or the WIFI AP.
  • FIG. 1 it is a schematic diagram of a system architecture in which a LAA system and a WiFi system coexist in the technical solution provided by the embodiment of the present invention.
  • FIG. 1 shows a deployment location between a plurality of eNBs (base stations) and a plurality of WIFI APs, and each eNB And the coverage of each WIFI AP and its relationship.
  • the probability of co-channel interference in the overlapping coverage is large. Therefore, the denser the layout of the LAA system and the WiFi system, the greater the probability of co-channel interference.
  • FIG. 1 is only a schematic diagram of a system architecture to which the embodiments of the present invention are applied, and is not intended to limit the scenarios to which the embodiments of the present invention apply.
  • the base station in the LAA system generally adopts the following two mechanisms for channel detection on the unlicensed channel, and one is based on duty cycle detection (or channel load detection), that is, Cell On/Off mechanism; one is idle channel detection, ie LBT mechanism.
  • the base station For the Cell On/Off mechanism, the base station first detects the load level of a group of unlicensed channels in one Cell On/Off period, and then selects the unlicensed channel with the lowest load rate, and according to the duty of the unlicensed channel with the lowest load rate. Compared with the detection result, the on/off ratio allocation of the LAA system is determined, that is, the scheduling duration of the base station in a Cell On/Off period; wherein the scheduling duration is generally above tens of milliseconds (ms). Under the Cell On/Off mechanism, the LAA system can support CCA or not.
  • the base station starts the CCA once before sending the data packet. If the detection result of the CCA is no collision (that is, the unlicensed channel is idle), the data packet can be sent; if the detection result of the CCA is a conflict (ie, non- If the authorized channel is not idle, the extended CCA is performed by selecting a random number, and the data packet is not sent until the accumulated idle time corresponding to the extended duration is detected. For example, if the base station selects the random number N, the CCA is performed again at least within the N*CCA detection duration, and based on the detection result, it is determined whether to transmit the data packet, that is, whether the unlicensed channel is occupied.
  • the physical frame structure of the WiFi that is, the physical layer convergence procedure protocol data unit (PPDU) frame format.
  • PPDU physical layer convergence procedure protocol data unit
  • the WiFi physical frame structure may include: a physical layer convergence procedure (PLCP) preamble, a signal field, and a data field.
  • the WiFi physical frame structure may include: a PLCP preamble, a PLCP header, a PLCP service data unit (PSDU), and a tail field. And the pad field.
  • PLCP physical layer convergence procedure
  • PSDU PLCP service data unit
  • the PLCP Header includes: a rate field, a reserved field, a length field, a parity field, a tail field, and a service field. From the modulation point of view, the rate field, the reserved field, the length field, and the parity field, the tail field constitutes an independent orthogonal frequency division multiplexing (OFDM) symbol, which is recorded as a signal field.
  • OFDM orthogonal frequency division multiplexing
  • the WiFi control frame includes a request to send (RTS) frame and a clear to send (CTS) frame. It should be noted that the WiFi control frame in this document refers to an RTS frame or a CTS frame.
  • FIG. 3 it is a schematic diagram of an RTS frame structure.
  • the RTS frame shown in FIG. 3 includes: a media access control (MAC) header and a frame check sequence (FCS), wherein the MAC header includes: a frame control field and a duration ( The duration address or receiving station address (RA) field and the sender address or transmitting station address (TA) field; the number of bytes occupied by these fields can be: 2, 2 6, 6, 4, that is, the RTS frame format generally occupies 20 bytes.
  • MAC media access control
  • FCS frame check sequence
  • FIG. 4 it is a schematic diagram of a CTS frame structure.
  • the CTS frame shown in FIG. 4 includes: a MAC header and an FCS, wherein the MAC header includes: a frame control field, a duration field, and an RA field; the number of bytes occupied by these fields may be: 2, 2, 6, and 4, respectively. That is, the CTS frame generally occupies 14 bytes.
  • the Duration field in the RTS frame and the CTS frame is used to record the value of the network allocation vector (NAV), that is, the channel occupation time
  • the duration field may be referred to as a NAV field.
  • FIG. 5 is a flowchart of a method for transmitting a channel reservation signal according to an embodiment of the present invention.
  • the method shown in FIG. 5 includes the following steps S101-S102:
  • the base station detects whether a system signal is received on the unlicensed channel.
  • step S101 may include: if the base station needs to occupy an unlicensed channel, the base station detects whether a system signal is received on the unlicensed channel within a preset time period.
  • step S101 may include: if the base station needs to occupy the unlicensed channel, detecting whether the system signal is received on the unlicensed channel when the LAA system to which the LAA system belongs is at cell off or CCA.
  • the base station needs to occupy the unlicensed channel. It can be understood that the base station needs to communicate with the terminal connected to the base station through the unlicensed channel. The base station detects whether a system signal is received on the unlicensed channel. It can be understood that the base station detects whether the system signal is received at a frequency point corresponding to the unlicensed channel. System signals include the same system signal or a different system signal.
  • the base station can detect the WiFi signal preamble
  • the code determines if a WiFi signal is received.
  • the WiFi signal preamble is a fixed frequency domain sequence. Therefore, the base station can correlate the received signal on the unlicensed channel with a fixed frequency domain sequence, and if the correlation peak exists, it is considered to exist.
  • the WiFi signal preamble that is, it is detected that the WiFi signal has been received.
  • the method may further include: after detecting the WiFi signal preamble, the base station detects a length field in the PLCP header, so that the base station may determine a duration of the current frame of the WiFi signal. In this way, in step S102, the base station may transmit a channel reservation signal after the end of the current frame of the WiFi signal to avoid interference of the WiFi service data in the current frame on subsequent LAA service data.
  • the method may further include: after detecting the WiFi signal preamble, the base station detects the NAV field in the MAC header.
  • a data transmission process may involve multiple data interaction processes, such as an interaction process in which a WIFI AP transmits a data packet and receives a corresponding acknowledgement (ACK) feedback, and the NAV field is used to mark a data transmission process.
  • the base station may send a channel reservation signal after the end of the data transmission process of the WiFi signal to avoid the WiFi service data transmitted during the current data transmission to the subsequent LAA service data. The interference caused.
  • the base station detects that the system signal is received on the unlicensed channel, indicating that the same system or a different system is deployed around the LAA system to which the base station belongs, that is, other base stations or WIFI APs are deployed around the base station; and, the current time has the same system or different The system occupies the unlicensed channel.
  • Step S102 may include: if the base station detects that the system signal is received on the unlicensed channel, the base station sends a channel on the unlicensed channel to the network element (such as a WIFI AP or another base station, etc.) in the system to which the system signal belongs.
  • a reservation signal is reserved to reserve the unlicensed channel.
  • the channel reservation signal carries the length of time to be reserved.
  • the duration of the pending subscription is the duration of the LAA service data that needs to be sent this time.
  • the channel reservation signal conforms to the WiFi frame format.
  • the WiFi control frame may be used to represent the channel reservation signal, and the NAV field is used to mark part or all of the reserved time length; or the combination of the WiFi signal preamble and the signal field may be used to indicate the channel reservation signal, specifically by using the length field to mark the part or All the time to be reserved.
  • the method may further include: after transmitting the channel reservation signal, the base station sends the LAA service data to the terminal within a waiting time period.
  • the method may further include: if the base station detects that the system signal is received on the unlicensed channel within the preset time period, the base station may directly occupy the unlicensed channel without using the sending channel. A reservation signal is reserved to reserve the unlicensed channel.
  • the base station may also perform CCA first; if the detection result of the CCA is that the unlicensed channel is idle, the base station reserves the channel reservation signal to reserve the unlicensed channel, and the specific implementation manner may refer to the related implementation in this document. example.
  • the optional implementation manner can prevent the base station from actually receiving the system signal on the unlicensed channel, but cannot successfully parse the system signal, and mistakenly believes that the system signal is not received on the unlicensed channel, thereby causing the base station to directly occupy the non-authorized channel.
  • the system in which the system signal is located interferes with the LAA service data by the service data transmitted on the unlicensed channel.
  • the same system or a different system can be deployed around the LAA system to which the base station belongs.
  • the LAA system needs to occupy an unlicensed channel, if the unlicensed channel is being occupied by a certain system or a different system, the same system or Different systems will cause co-channel interference to the LAA system.
  • the base station may send a channel reservation signal to reserve the unlicensed channel after determining that the unlicensed channel is occupied by the same system or a different system.
  • the same system and different systems do not exist around the LAA system to which the base station belongs, or the same system and different systems around the LAA system to which the base station belongs do not work for a long time due to faults, etc., and the base station can directly By occupying the unlicensed channel, that is, without transmitting a channel reservation signal, the unlicensed channel can be utilized to communicate with the terminal.
  • the base station may process the channel reservation signal by using a lower modulation mode and a lower coding rate, for example,
  • the minimum modulation method specified in 802.11 is binary phase shift keying (BPSK), and the lowest coding rate is 1/2.
  • the channel reservation signal is transmitted to reserve the unlicensed channel. Compared with the prior art, a certain amount of resources can be saved compared to transmitting a channel reservation signal each time an unlicensed channel needs to be occupied.
  • the system signal is a WiFi signal; the length of the reservation to be reserved is T; the maximum duration of the reservation of the combination of the WiFi signal preamble and the signal field is a, and the maximum duration of the reservation of the WiFi control frame is b;
  • the base station sends the channel reservation signal on the unlicensed channel, which may include the following situations:
  • the base station transmits a channel reservation signal represented by a combination of a set of WiFi signal preambles and a signal field on the unlicensed channel, or a channel reservation signal represented by a set of WiFi control frames.
  • the base station transmits a channel reservation signal represented by a combination of a plurality of sets of WiFi signal preambles and a signal field on the unlicensed channel, or a channel reservation signal represented by a set of WiFi control frames.
  • the base station transmits, on the unlicensed channel, a channel reservation signal represented by a combination of multiple sets of WiFi signal preambles and signal fields, or a channel reservation signal represented by multiple sets of WiFi control frames, or a group/multiple A channel reservation signal represented by a combination of a group of WiFi signal preambles and a signal field and a channel reservation signal represented by one or more sets of WiFi control frames.
  • This alternative embodiment may be based on a Cell On/Off mechanism or an LBT mechanism.
  • the set of channel reservation signals includes one or more channel reservation signals; when a group of channel reservation signals includes a plurality of channel reservation signals, the plurality of channel reservation signals may be consecutive multiple channel reservation signals, or may be carried in Multiple channel reservation signals on multiple consecutive OFDM symbols.
  • the plurality of channel reservation signals are used to increase the receiver of the channel reservation signal (eg, WIFI AP or The reception success rate and the decoding success rate of the other base stations, etc., but the purpose of the same group of channel reservation signals is to reserve the same period of time, which is part or all of the length of the reservation to be reserved. For details, refer to the example below.
  • the combination of the WiFi signal preamble and the signal field uses the length field to reserve the duration.
  • the length field occupies 12 bits.
  • the length field ranges from 0 to 4095.
  • the system bandwidth is 20 MHz.
  • the length of one OFDM symbol is 4 us (microseconds).
  • the indicated modulation mode is BPSK.
  • the length indicated by the length field is the largest, specifically 5.464 ms, which is about 5 ms. That is, a combination of a set of WiFi signal preambles and a signal field is sent, and a maximum of about 5 ms can be reserved.
  • the RTS frame or CTS frame uses the NAV field to reserve the duration.
  • a Duration field ie, a NAV field
  • a 5 ms
  • b 32 ms. It should be understood by those skilled in the art that when the modulation mode and the coding rate indicated by the RATE field change, the length of the length field and the NAV field can be changed accordingly. In this case, the values of a and b should also be The corresponding changes will not be repeated here.
  • the base station transmits a set of channel reservation signals
  • the length of time reserved for the set of channel reservation signals is equal to the length of time to be reserved.
  • the base station transmits a plurality of sets of channel reservation signals the sum of the durations reserved by the plurality of sets of channel reservation signals is equal to the length of time to be reserved.
  • the durations reserved for each group of channel reservation signals may be the same or different.
  • the types of channel reservation signals of each group may be the same or different. For example, if the base station needs to send two sets of channel reservation signals, the two sets of channel reservation signals may all be represented by using a WiFi control frame; and the WiFi signal preamble may also be used.
  • the base station transmits the previous one.
  • the time interval between the group channel reservation signal and the latter group of channel reservation signals is equal to the duration of the previous group of channel reservation signals, wherein the "time interval" refers to the end time of transmitting the previous group of channel reservation signals to the group of channels after transmission. The time between the start of the reservation signal.
  • the base station first transmits the previous set of channel reservation signals, and then transmits the LAA service data to the terminal within the reserved time period of the previous set of channel reservation signals; then, transmits the latter set of channel reservation signals, and then the latter group
  • the LAA service data is transmitted to the terminal within a predetermined period of time reserved by the channel reservation signal; and so on, until the total length of time that the transmitted plurality of sets of channel reservation signals are reserved is equal to the length of time to be reserved.
  • the "time interval" may be slightly smaller than the duration of the previous group of channel reservation signals.
  • the base station transmits two sets of channel reservation signals, and the first group channel reservation signal is represented by a WiFi control frame, and the reserved duration is 32 ms, and the second group channel reservation signal uses a WiFi signal preamble.
  • the combination of the code and the signal field indicates that the reserved time is 5 ms; the time interval between the base station transmitting the first group channel reservation signal and transmitting the second group channel reservation signal is slightly less than 32 ms, as shown in FIG.
  • a shaded rectangle in FIG. 6 may represent a channel reservation signal, and may also represent one OFDM symbol.
  • Fig. 6 is a diagram showing a marking method based on the reservation duration of the channel reservation signal described in the following mode 3, and examples based on other modes are similar here, and are not listed here.
  • the base station transmitting the channel reservation signal on the unlicensed channel may include: the base station transmitting the first channel reservation signal on the unlicensed channel, and sending the second channel reservation after the preset time period. a signal; wherein, the modulation order of the data transmitted on the subframe in which the second channel reservation signal is located is less than or equal to the modulation order of the data transmitted on the subframe reserved by the first channel reservation signal, and the second channel reservation signal is located Subframe
  • the coding rate of the data transmitted on is less than or equal to the coding rate of the data transmitted on the subframe reserved by the first channel reservation signal.
  • the optional embodiment may be applicable to the following scenario: after the base station sends the second channel reservation signal, the second channel reservation signal has a remaining duration on the subframe occupied by the second channel reservation signal, and the base station schedules the remaining duration of the subframe.
  • LAA business data after the base station sends the second channel reservation signal, the second channel reservation signal has a remaining duration on the subframe occupied by the second channel reservation signal, and the base station schedules the remaining duration of the subframe.
  • the base station may send multiple first channel reservation signals on the unlicensed channel (which may be equivalent to the above-mentioned group of channel reservation signals); and send multiple after the reserved time period (which may be equivalent to the above-mentioned time interval)
  • the second channel reservation signal (which may correspond to another set of channel reservation signals described above).
  • the base station can transmit LAAs of 3 subframes (including subframes 1, 2, and 3) after transmitting the first channel reservation signal of the group.
  • Service data assuming that the transmission time of a group of second channel reservation signals is 2.5 ms (ie, the occupied subframe is subframe 3), the LAA transmitted on subframe 3 (specifically, the first half of subframe 3)
  • the modulation order and coding rate of the data may be less than or equal to the modulation order and coding rate of the LAA service data transmitted in the first and second subframes.
  • the modulation order of the data of the LAA transmitted on the first and second subframes is 64 quadrature amplitude modulation (QAM), the coding rate is 0.93, and the modulation order of the data of the LAA transmitted on the third subframe.
  • the number is 16QAM and the code rate is 0.48.
  • the base station may notify the MCS (including the modulation mode, the modulation order, the coding rate, and the like) of the data in each subframe of the terminal by using downlink control infornation (DCI).
  • DCI downlink control infornation
  • step S102 may include: if the base station detects that the system signal is received on the unlicensed channel, performing CCA; if the detection result of the CCA is that the unlicensed channel is idle, the base station is A channel reservation signal is transmitted on the unlicensed channel to reserve the unlicensed channel.
  • This alternative embodiment may be based on a Cell On/Off mechanism or an LBT mechanism.
  • the CCA may be performed before each time the group of channel reservation signals are transmitted.
  • the CCA may be performed before each time a group of channel reservation signals are transmitted; in addition, in this case, optionally, when the base station transmits the previous group of channel reservation signals and When the time interval between a set of channel reservation signals is less than the duration of the previous set of channel reservation signals, the base station may perform CCA only before transmitting the first group of channel reservation signals in the plurality of sets of channel reservation signals.
  • the base station does not perform any operation before transmitting the channel reservation signal, which may not be able to receive the channel reservation signal due to the system in which the interference may be caused by the system, so that the transmission of the channel reservation signal has no meaning.
  • This not only wastes resources, but also does not achieve the purpose of reserved channels and avoiding co-channel interference.
  • the optional embodiment can ensure that the unlicensed channel is idle when the base station sends the channel reservation signal, that is, no unlicensed channel is occupied by the same system and different systems, that is, the same signal of the system is located.
  • the system or the different system is not in the transmitting state (ie, in the receiving state), such that the probability that the channel reservation signal sent by the base station is received by the same system or different system in which the system signal is located is increased, so that the reserved channel is reached and the same frequency is avoided.
  • the probability of interference is increased.
  • T1 is a delay of the LAA system to which the base station belongs to switch from the uplink transmission to the downlink transmission, where T1 is greater than or equal to 0; and T2 is a time required for the base station to send the channel reservation signal to the air interface, where T2 is greater than or equal to zero.
  • the base station sends the channel reservation signal on the unlicensed channel to reserve the unlicensed channel, which may include: if the detection result of the CCA is that the unlicensed channel is idle, and T1 ⁇ T2, then the base After the end of the CCA detection, the delay time T1-T2 is delayed, and the channel reservation signal is started to be transmitted on the unlicensed channel to reserve the unlicensed channel, as shown in FIG. 6(a). In this way, it can be ensured that the LAA system has switched from the uplink transmission to the downlink transmission when the base station transmits the channel reservation signal in the air interface.
  • the base station transmits a channel reservation signal on the unlicensed channel to reserve the unlicensed channel. Specifically, if the detection result of the CCA is that the unlicensed channel is idle, and T1 ⁇ T2, the base station immediately transmits a channel reservation signal on the unlicensed channel, as shown in FIG. 6(b). In this way, other systems can be prevented from preempting the unlicensed channel.
  • the optional implementation may be applied to the LBT mechanism or the Cell On/Off mechanism.
  • FIG. 6(a) and FIG. 6(b) only indicate the reference numerals of the drawings, and FIG. No affiliation.
  • the base station needs to switch from the uplink transmission to the downlink transmission during the CCA detection or after the CCA detection ends.
  • the uplink transmission refers to a process in which the base station receives the system signal
  • the downlink transmission refers to a process in which the base station transmits the channel reservation data.
  • T2 refers to the time required for the base station to extract the channel reservation signal from the storage unit until the channel reservation signal is transmitted to the air interface; if the channel reservation signal is at the base station
  • the T2 is generated by the base station when the channel reservation signal is taken out from the generating unit until the channel reservation signal is transmitted to the air interface.
  • the manner of acquiring T1 and T2 is not limited in the embodiment of the present invention.
  • the CCA provided by the embodiment of the present invention may be an enhanced CCA, that is, a certain improvement is performed on the basis of the CCA provided by the prior art, and the improvement may be implemented by reducing the detection threshold of the CCA and/or extending the detection duration. And / or extend the length of the defer.
  • the detection threshold of the CCA can be set low enough to enable the base station to detect a different system signal with a smaller transmission power.
  • the detection threshold of the CCA is less than or equal to d, where d represents a detection threshold of the base station when performing CCA on the same system and a detection threshold when performing CCA on the different system. value.
  • the system bandwidth is 20 MHz
  • the different system is the WiFi system.
  • the detection threshold of the base station to the same system is generally -52 dBm, for the WiFi system.
  • the detection threshold is generally -72dBm, and the value of d can be -82dBm or even -92dBm.
  • One of ordinary skill in the art will appreciate that as system bandwidth changes and/or types of different systems change, the value of d will also change accordingly.
  • the base station can extend the detection duration of the CCA, thereby improving the accuracy of detecting the CCA by the base station.
  • the detection duration of the CCA is greater than or equal to the detection duration of the CCA when the base station performs CCA and the detection duration of the CCA when the dissimilar system is performed.
  • the detection duration of the CCA in the optional implementation is greater than or equal to the detection duration when the base station performs CCA on the WiFi system in the prior art.
  • the defer delay of the WiFi is 34us.
  • the LAA optional defer duration can be configured to be greater than or equal to 43us.
  • the delay is first performed for a period of time (ie, the DEA optional defer duration), and then the CCA is started.
  • the process from the start of the delay to the output of the CCA detection result is referred to as a CCA.
  • the base station can extend the duration of the defer, so that the detection duration of the CCA can be prolonged, thereby prolonging the detection duration of the CCA, so as to improve the detection accuracy of the CCA by the base station.
  • the defer duration in the CCA process in the embodiment of the present invention is greater than or equal to the defer duration when the base station performs CCA on the same system, and the defer duration in the CCA of the dissimilar system. Maximum value. For a specific example, reference may be made to the above, and details are not described herein again.
  • the base station detecting whether the system signal is received on the unlicensed channel may include: detecting, by the base station, whether the system signal is received on the unlicensed channel in each detection period; Wherein, one detection period includes one or more detection durations.
  • This alternative embodiment may be based on a Cell On/Off mechanism or an LBT mechanism.
  • Each detection period is the same.
  • One detection period may include one or more Cell Off durations (that is, the duration of one Cell Off) or a CCA duration.
  • the CCA duration refers to the duration of time that the base station performs CCA, CCA. Duration can be
  • the defer duration of the system to which the system signal belongs is the length of time required for the counter to be reduced to 0 during the CCA detection process.
  • the system is a WiFi system, and the defer duration is 34 us or 43 us.
  • the length of any two detections may be the same or different.
  • One Cell Off duration or one CCA duration may include one or more detection durations.
  • one detection duration may also be distributed over multiple Cell Off durations or multiple CCA durations.
  • the total detection duration (ie, the sum of the detection durations) in each detection period is greater than or equal to a preset threshold. The larger the value of the preset threshold is, the higher the accuracy of the detection system signal is.
  • the detection period and detection duration can be in units of seconds or in units of hundred milliseconds or milliseconds.
  • FIG. 7 it is a schematic diagram of the relationship between the detection period P and the detection duration T.
  • the base station detects whether a system signal is received on the unlicensed channel when the cell is off, and the horizontal axis represents the time axis, and the time period occupied by the rectangular frame indicates that the base station is in Cell On, two rectangles. The time period between the boxes indicates that the base station is in Cell Off.
  • a detection period P includes a number of Cell Off durations, and two of the Cell Off durations include durations T1 and T2, respectively.
  • T1 and T2 can be used as one detection duration
  • T1+T2 can be used as a detection. duration.
  • the optional embodiment provides a large granularity detection period and a small granularity detection duration, wherein a large granularity detection period can avoid detection of missing system signals, and a small granularity detection duration enables the base station to quickly detect system signals. .
  • the embodiment of the invention further provides a technical solution for adjusting the size of the detection period, and specifically, the size of the detection period can be adjusted according to the length of time to be reserved.
  • the system signal is a WiFi signal
  • the length of the detection period may be adjusted according to the duration indicated by the length field or the duration indicated by the NAV field. For example, if the length indicated by the length field or the NAV field is greater than the detection period, the detection period may be increased, and the adjusted detection period is enabled the next time the system signal is detected.
  • the base station performing the CCA may include: if the base station detects that the system signal is received on the unlicensed channel within any one of the detection durations, stopping detecting the system signal during the detection period to which the detection duration belongs, and performing CCA.
  • the performing, by the base station, the CCA may include: in the Cell On/Off mechanism, the base station starts CCA in N subframes before the LAA system to which the LAA system belongs is in the cell; wherein, the N sub-subs The duration of the frame is greater than or equal to the maximum duration of a data transmission of the system to which the system signal belongs.
  • the base station when the base station is greater than or equal to the system signal before the LAA system to which it belongs is in Cell On,
  • the CCA is started at the time when the maximum duration of the data transmission of the system starts. Once the time is detected, the channel reservation signal is started to be transmitted immediately or the channel reservation signal is started to be transmitted in the next OFDM symbol. In this way, the base station can quickly preempt the unlicensed channel.
  • the detection result of the CCA is that the time when the unlicensed channel is idle is marked as "idle time" in the drawings of the present application.
  • the length of the Cell On and the length of the Cell Off are fixed for a long period of time, and only after a period of duty cycle measurement is possible, that is, the Cell
  • the duration of On and the length of Cell Off are relatively fixed, so the cut-off point between Cell On and Cell Off is generally fixed.
  • This embodiment changes the demarcation point between Cell On and Cell Off, specifically the time at which the base station transmits the channel reservation signal as a new demarcation point.
  • the time when the CAA detection result is that the channel is idle is taken as a new demarcation point.
  • the different system is a WiFi system
  • the WiFi system is performing a data transmission process, and the data transmission process ends before the original boundary point.
  • the new boundary point is before the original boundary point.
  • the WiFi system is in the process of two data transmissions, then the second data
  • the technical moment of the transmission process is after the original demarcation point.
  • this alternative embodiment enables the original demarcation point to be advanced or delayed.
  • the duration of the N subframes indicates the maximum duration of the data transmission of the WiFi system, that is, the transmission opportunity (TXOP). Since the maximum value configured for the TXOP is generally 8 ms, that is, 8 sub-frames. frame.
  • TXOP transmission opportunity
  • FIG. 8 a schematic diagram of a triggering timing of a CCA provided for this embodiment is shown.
  • the boundary points of the original Cell On and Cell Off ie, the original demarcation point
  • the boundary points of the original Cell On and Cell Off are the start boundaries of the subframes of the n-1th subframe and the nth subframe, and 8 subframes before the boundary point ( That is, the n-8th subframe) starts the CCA.
  • the shaded rectangle in Fig. 8 indicates a set of channel reservation signals, and the new cutoff point in Fig. 8 is taken as an example before the original cutoff point.
  • the base station transmitting the channel reservation signal on the unlicensed channel may include: in the Cell On/Off mechanism, on the unlicensed channel, the base station before the LAA system to which the base station belongs is in Cell On A channel reservation signal is transmitted on one or more OFDM symbols. The duration of the one or more OFDM symbols is within the Cell On timing duration.
  • multiple identical channel reservation signals are repeatedly transmitted on one or more OFDM symbols.
  • FIG. 9 it is a schematic diagram of a transmission channel reservation signal provided by the optional embodiment.
  • the channel reservation signal is transmitted on one OFDM symbol before Cell On as an example, and the hatched rectangle indicates one OFDM symbol.
  • the original demarcation point and the new demarcation point are shown in Figure 9.
  • the optional embodiment can be applied to a scenario in which a channel reservation is performed by an LAA system that does not have a CCA function, that is, in an LAA system that does not have a CCA function, an unlicensed channel can be reserved.
  • the base station can directly reserve the unlicensed channel by using the optional embodiment without performing CCA without the high-throughput service of the same system or different systems.
  • the base station transmitting the channel reservation signal on the unlicensed channel may include: in the Cell On/Off mechanism, on the unlicensed channel, when the base station is in Cell On, when the LAA system to which the base station belongs, The channel reservation signal is transmitted on one or more OFDM symbols starting with Cell On. The duration of the one or more OFDM symbols is within the Cell On timing duration.
  • multiple identical channel reservation signals are repeatedly transmitted on one or more OFDM symbols.
  • the optional embodiment may be applicable to a scenario in which CCA is not performed, that is, after the base station detects that the system signal is received, the channel reservation signal may be directly transmitted on one or more OFDM symbols at the start of the Cell On. . Further optionally, the channel reservation signal is sent on each OFDM symbol in one subframe or multiple subframes started by Cell On, so that the reception performance of the channel reservation signal can be improved; in addition, in the further optional implementation manner
  • the timing problem of the hybrid automatic repeat request (HARQ) may be automatically corrected by the LAA system, or the subframe in which the LAA system sets the transmission channel reservation signal is not scheduled. This alternative embodiment does not change the demarcation point between Cell On and Cell Off.
  • the base station transmitting the channel reservation signal on the unlicensed channel may include: in the Cell On/Off mechanism, on the unlicensed channel, when the base station is in Cell On, when the LAA system to which the base station belongs, The channel reservation signal is transmitted on the OFDM symbols of one or more data regions from which Cell On starts. The duration of the one or more OFDM symbols is within the Cell On timing duration.
  • multiple identical channel reservation signals are repeatedly transmitted on one or more OFDM symbols.
  • the optional embodiment may be applicable to a scenario in which CCA is not performed, that is, after the base station detects that the system signal is received, the channel may be directly transmitted on the OFDM symbol of one or more data regions starting from Cell On.
  • the reservation signal that is, the channel reservation signal may not be transmitted on the OFDM symbol of the control region, thus avoiding HARQ timing issues.
  • the channel reservation signal is repeatedly transmitted on the OFDM symbol of each data area within one subframe or one of the multiple subframes started by Cell On. This alternative embodiment does not change the demarcation point between Cell On and Cell Off.
  • the explanation about the OFDM symbol of the control region and the OFDM symbol of the data region can be referred to below.
  • the Cell On/Off mechanism if the duration of the Cell On is greater than the maximum reserved duration supported by the channel reservation signal, the Cell On duration may be within the duration of the Cell On.
  • One or more consecutive channel reservation signals are continuously transmitted to prevent other systems from preempting the unlicensed channel within the duration of the Cell On. For example, if the duration of the Cell On is 40 ms and the maximum reservation duration supported by the channel reservation signal is 32 ms, in the implementation manner in which the demarcation point does not change, the base station can reserve 8 ms after the reservation for 32 ms, to reserve the full Cell.
  • the duration of On is 40ms.
  • one or a plurality of channel reservation signals that are considered to be the maximum reservation duration supported by the reserved channel reservation channel are a group of channel reservation signals, and the remaining duration of the reservation Cell On is reserved.
  • the channel reservation signal is another group of channel reservation signals, and the specific implementation of the two groups of channel reservation signals can be referred to other examples in this document, and details are not described herein again.
  • the base station transmitting the channel reservation signal on the unlicensed channel may include: the base station continuously transmitting S channel reservation signals on the unlicensed channel; wherein, the reservation of the sth channel reservation signal The field is used to mark the sum of the duration occupied by the s+1 channel reservation signal to the S channel reservation signal and the duration to be reserved; wherein 1 ⁇ s ⁇ S, S and s are integers, and the waiting time is The length of time required to transmit data on this unlicensed channel.
  • This alternative embodiment may be based on a Cell On/Off mechanism or an LBT mechanism.
  • the optional embodiment can be understood as: when the detection result of the CCA is that the unlicensed channel is idle, a plurality of channel reservation signals are immediately transmitted; and, the channel reservation signal in this embodiment is independent of the OFDM symbol.
  • the end time at which the base station sends the S channel reservation signals may be the next subframe start boundary or may not be the next subframe start boundary.
  • the modulation mode and the coding mode of the S channel reservation signals may be different.
  • the base station may adjust the duration of the channel reservation signal by adjusting the modulation and coding mode of the reservation signal, so as to align the start boundary of the next subframe as much as possible.
  • the base station transmits a channel reservation signal at a fixed position of one subframe, for example, a channel reservation signal is transmitted at a position such as a subframe start boundary or a third OFDM symbol after a subframe start boundary.
  • the optional embodiment can avoid the prior art that the base station is transmitting the channel reservation signal at a fixed location, and the result of the detection from the CCA is that the unlicensed channel is idle to the location of the fixed transmission channel reservation signal.
  • the problem that the unlicensed channel is preempted by the same system or different systems occurs, so that the LAA system where the base station is located can quickly make an appointment to the unlicensed channel.
  • S>1 that is, the base station transmits a plurality of channel reservation signals, it is possible to improve the reception success rate and the decoding success rate of the channel reservation signal by the receiver of the channel reservation signal.
  • the plurality of channel reservation signals can be understood as a set of channel reservation signals as described in the above alternative embodiments.
  • the reservation field of the channel reservation signal refers to the NAV field; when the channel reservation signal is represented by a combination of the WiFi signal preamble and the signal field, the reservation field of the channel reservation signal refers to the length field.
  • the reservation field of the sth channel reservation signal is sufficient to mark the sum of the duration occupied by the s+1 channel reservation signal to the S channel reservation signal and the length of the to-be-served time as an example.
  • the duration of the channel reservation signal occupied represented as T 0, long represents time until the reservation is T
  • the S channel reservation duration of the reservation fields for each channel signal reservation signal to be marked are as follows: first a channel reservation signal The duration of the reservation field is (S-1)*T 0 +T, and the duration of the reservation field of the second channel reservation signal is (S-2)*T 0 +T...the sth channel reservation
  • the duration of the reserved field of the signal is (Ss)*T 0 +T...
  • the duration of the reserved field of the S-th channel reservation signal is T.
  • FIG. 10 it is a schematic diagram of a transmission channel reservation signal provided by this embodiment.
  • the base station transmitting the channel reservation signal on the unlicensed channel may include: the base station transmitting on each target OFDM symbol on the unlicensed channel.
  • a channel reservation signal where the target OFDM symbol refers to P OFDM symbols starting from the first OFDM symbol after the OFDM symbol at the target time, and the target time is a time when the base station determines that the detection result of the CCA is that the unlicensed channel is idle.
  • P is an integer greater than or equal to 1.
  • the detection result of the CCA is that the time when the unlicensed channel is idle is the symbol boundary between the i-th OFDM symbol and the i+1th OFDM symbol
  • the detection result of the CCA is the moment when the unlicensed channel is idle.
  • the OFDM symbol in which it is is the i-th OFDM symbol; where i is an integer.
  • the detection result of the CCA is that the moment when the unlicensed channel is idle may not be the OFDM symbol boundary, in this case, the OFDM symbol at which the moment is located is considered to be an incomplete OFDM symbol, and the other OFDM symbols are complete OFDM symbols.
  • the optional embodiment can be understood as: the first OFDM symbol after the OFDM symbol occupied by the unauthorized channel is used to start transmitting the channel reservation signal; and the channel reservation signal is sent with the OFDM symbol as time. Units.
  • the “multiple OFDM symbols” in this embodiment may be a group of OFDM symbols, where the group of OFDM symbols is composed of consecutive multiple OFDM symbols; or may be multiple groups of OFDM symbols, where each group of OFDM symbols is composed of one OFDM symbol Or consist of a plurality of consecutive OFDM symbols, the different groups are separated by a certain time interval.
  • time interval For related explanations of the time interval, reference may be made to the related embodiments above, and details are not described herein again.
  • FIG. 11 is a schematic diagram of a transmission channel reservation signal according to an embodiment of the present invention.
  • the system signal is a WiFi signal as an example
  • the target OFDM symbol is a plurality of consecutive OFDM symbols.
  • Each target OFDM symbol is sent Send a channel reservation signal.
  • Each white rectangle in FIG. 11 represents one OFDM symbol, one subframe is composed of 14 OFDM symbols, a part of a white rectangle is covered with a hatched rectangle, and a hatched rectangle represents a channel reservation signal.
  • a channel reservation signal is insufficient. Fill in an OFDM symbol.
  • each OFDM symbol in the LAA system occupies about 71 us, where The duration of the first OFDM symbol of each slot is about 71.875 us, and the duration of the non-first OFDM symbol of each slot is about 71.35 us.
  • each OFDM symbol in the LAA system occupies approximately 83.33 us. In the following, the duration occupied by an OFDM symbol with a normal CP is 71 us, and the duration of an OFDM symbol with an extended CP is 83 us.
  • the duration of the WiFi control frame is different; wherein, when the modulation mode is BPSK, the coding rate is At the same time, the RTS frame and the CTS frame occupy the largest duration, which are 52us and 44us respectively. Therefore, when the WiFi control frame is used to represent the channel reservation signal, the maximum value of the duration occupied by one channel reservation signal is 52us or 44us.
  • the duration occupied by the WiFi signal preamble is 16 us, the signal field occupies 1 OFDM symbol of the WiFi system, that is, 4 us. Therefore, when the channel reservation signal is represented by a combination of the WiFi signal preamble and the signal field, a channel reservation signal is used. The duration of the occupation is 20us. Therefore, whether a channel control signal is represented using a WiFi control frame or a channel reservation signal is represented using a combination of a WiFi signal preamble and a signal field, one channel reservation signal is insufficient to fill one OFDM symbol.
  • the LAA data LAA service data may be sent in a subframe in which the channel reservation signal is sent, or the LAA data LAA service data may not be sent. Based on the LAA data LAA service data not transmitted on the subframe where the channel reservation signal is located, the following list A method of determining a target OFDM symbol:
  • the base station may The OFDM symbol is used as the target OFDM symbol, as shown in FIG.
  • the OFDM symbol is used as the OFDM symbol.
  • the target OFDM symbol, or both the OFDM symbol and the next subframe are the target OFDM symbols, as shown in FIG.
  • the OFDM in the next subframe The symbol is used as the target OFDM symbol as shown in FIG.
  • each rectangle in FIGS. 12-14 represents one OFDM symbol
  • each shaded rectangle represents one target OFDM symbol.
  • the method for determining an OFDM symbol shown in FIG. 12-14 is described by taking the last target OFDM symbol as a starting boundary of a certain subframe as an example.
  • the specific implementation time is not limited thereto.
  • the base station may detect the result from the CCA.
  • a fixed number of OFDM symbols starting from the first OFDM symbol after the OFDM symbol occupied by the unlicensed channel is used as the target OFDM symbol.
  • the multiple OFDM symbols are consecutive multiple OFDM symbols, that is, the target OFDM symbols are consecutive multiple OFDM symbols.
  • the target OFDM symbol shown in FIG. 16 is taken as an example.
  • the OFDM symbol 2 in the subframe n (with 0 is the start symbol index in the subframe)
  • the result of the CCA detection is that the unlicensed channel is idle.
  • the target OFDM symbol may be the OFDM symbols 3 to 13 in the subframe n.
  • the system signal is a WiFi signal
  • the duration occupied by one RTS frame is 52 us
  • the length of the reserved time is 3 ms.
  • Manner 1 The reserved field of the channel reservation signal transmitted on the pth target OFDM symbol is used to mark the remaining duration after being occupied by the channel reservation signal on the pth target OFDM symbol; the channel reservation signal transmitted on the Pth target OFDM symbol The reserved field is used to mark the sum of the remaining duration after being occupied by the channel reservation signal on the Pth target OFDM symbol and the duration to be reserved; wherein 1 ⁇ p ⁇ P, p is an integer.
  • the mode 1 can be understood as a reservation according to an index of a target OFDM symbol, that is, a channel reservation signal transmitted on a different target OFDM symbol is reserved for a different duration, specifically: a non-last OFDM symbol and a last OFDM symbol.
  • the length of time reserved for the transmitted channel reservation signal is different.
  • the reserved field of the channel reservation signal transmitted on each target OFDM symbol is marked with the remaining duration of the target OFDM symbol occupied by the channel reservation signal, that is, each target OFDM symbol is reserved.
  • the remaining time is long, so that the unlicensed channel can be prevented from being preempted by the same system or different systems on the remaining duration of each target OFDM symbol.
  • the mode 1 can accurately reserve the length of time to be reserved by using the channel reservation signal transmitted on the last target OFDM symbol.
  • the receiver of the channel reservation signal needs to receive and parse the channel reservation signal transmitted on the last target OFDM symbol, and then the non-authorized channel can be avoided according to the time to be reserved.
  • the NAV field in the RTS frame on 12 is labeled 19us
  • the NAV field in the RTS frame on OFDM symbol 13 is labeled 19us + 3ms, as shown in FIG.
  • Mode 2 A reserved field of each channel reservation signal transmitted on each target OFDM symbol is used to mark the sum of the remaining duration after being occupied by the channel reservation signal on the target OFDM symbol and the duration to be reserved.
  • This mode 2 can be understood as a unified reservation, in which different OFDM symbols are sent.
  • the reserved channel reservation signals are reserved for the same duration. Therefore, it is not necessary to perform reservation according to the index of the OFDM symbol, and the implementation is simple.
  • the unlicensed channel can be prevented from being preempted by the same system or different systems in the remaining duration of each OFDM symbol.
  • the reserved field of the channel reservation signal transmitted on each target OFDM symbol is marked with the sum of the remaining duration of the target OFDM symbol occupied by the channel reservation signal and the time to be reserved, such that when the channel reservation signal is After receiving and successfully parsing the channel reservation signal transmitted on any one of the target OFDM symbols, the receiver may no longer receive and/or no longer parse the channel reservation signal transmitted on other target OFDM symbols; and the receiver successfully parses the last one. After the target OFDM symbol, an accurate waiting time period can be obtained.
  • the channel reservation signal is represented by the RTS frame
  • the target OFDM to which the normal CP is added the remaining duration after being occupied by the RTS frame on one target OFDM symbol is 19 us; thus, the RTS on the OFDM symbols 3 to 13
  • the NAV field in the frame is labeled 19us + 3ms, as shown in Figure 17.
  • Mode 3 The reserved field of the channel reservation signal transmitted on the mth target OFDM symbol is used to mark (P-m)* the sum of the OFDM symbol duration and the to-be-reserved duration; wherein 1 ⁇ m ⁇ P, m is an integer.
  • the mode 3 can be understood as a unified reservation, in which the channel reservation signals transmitted on different target OFDM symbols are reserved for different durations, and therefore, reservations need to be made according to the index of the OFDM symbols; but the channel reservation signals transmitted on different target OFDM symbols are The length of the appointment follows the same rules and is simple to implement. In addition, it is possible to prevent the unlicensed channel from being preempted by the same system or different systems over the remaining duration of each OFDM symbol. Moreover, since any one of the target OFDM symbols has reserved a time period from the start time of the target OFDM symbol to the end time of the LAA service data (where the transmission time period of the LAA service data is the time length to be reserved), A target OFDM symbol can accurately reserve the length of time to be reserved.
  • the receiver of the channel reservation signal receives and successfully parses any one After the channel reservation signal transmitted on the target OFDM symbol, the channel reservation signal transmitted on the other target OFDM symbols can no longer be received and/or parsed; and any target OFDM symbol can be successfully resolved by the receiver, Get an accurate length of time to be reserved.
  • OFDM symbol 3 is the first target OFDM symbol, and so on.
  • the NAV field in the RTS frame on the OFDM symbol 3 ie, the first target OFDM symbol
  • the NAV field in the RTS frame on OFDM symbol 4 ie, the 2nd target OFDM symbol
  • the NAV field in the RTS frame on OFDM symbol 4 ie, the 2nd target OFDM symbol
  • OFDM symbol 13 ie, the 11th target OFDM symbol
  • the NAV field in the RTS frame is marked as 3ms, as shown in Figure 18.
  • modes 1 to 3 may be used in combination, for example, a combination of the modes 1 and 3, or a combination of the modes 2 and 3 may constitute the mode 4.
  • the receiver of the channel reservation signal can correctly analyze the waiting time of the reservation as long as it receives any one of the target OFDM symbols in the latter part, so that the reception performance can be improved.
  • the receiver of the channel reservation signal can accurately reserve the waiting time of the reservation as long as the target OFDM symbol of the latter part is received, so that the reserved time can be improved. The accuracy of the length of time to be reserved.
  • OFDM symbols 3 to 11 are the former and OFDM symbols 12 to 13 are the latter.
  • the NAV field in the RTS frame on OFDM symbols 3-11 is labeled 19us, or 19us+3ms; the NAV field in the RTS frame on OFDM symbol 12 is labeled 71us+3ms, OFDM
  • the NAV field in the RTS frame on symbol 13 is labeled 3ms.
  • the above modes 1 to 4 may have other combinations, and are not enumerated here. Further, in any one of the above aspects 1 to 4, for the target OFDM symbol to which the extended CP is added, the duration of the NAV marked by the channel reservation signal indicated by the RTS frame transmitted on the OFDM symbol is similar thereto; and, when When a channel reservation signal is represented by a CTS frame, or a channel reservation signal is represented by a combination of a WiFi signal preamble and a signal field, a duration of a reservation field of a channel reservation signal on a target OFDM symbol is similar; Narration.
  • the padding information is also transmitted in the remaining duration of the target OFDM symbol occupied by the channel reservation signal (hereinafter referred to as "target channel reservation signal"), and the padding information may include but is not limited to any of the following information 1) to 3) Kind.
  • the padding information may be before the target channel reservation signal or after the target channel reservation signal; the target channel reservation signal may be represented by a WiFi control frame, or may be represented by a combination of a WiFi signal preamble and a signal field.
  • the padded WiFi control frame may be an RTS frame or a CTS frame.
  • the WiFi control frame is referred to as a first WiFi control frame
  • the filled WiFi frame is referred to as a second WiFi control frame.
  • the first WiFi control frame and the second WiFi control frame may be the same type of WiFi control frame, or may be different types of WiFi control frames; for example, regardless of whether the first WiFi frame is
  • the RTS frame is also a CTS frame
  • the second WiFi frame may be an RTS frame or a CTS frame.
  • the modulation mode and the coding rate of the first WiFi frame and the second WiFi frame may be the same or different.
  • the duration of one RTS frame ie, the second WiFi control frame
  • the NAV field of the second WiFi control frame is marked as 3us, as shown in FIG. 19, to prevent the unauthorized control channel from being preempted by the same system or different systems within the 3us.
  • the WiFi signal preamble and the signal field may be padded to the target OFDM symbol.
  • the remaining duration ie, 27us
  • the WiFi control frame as shown in FIG. 20, to prevent the unauthorized control channel from being preempted by the same system or different systems within the 7us.
  • the remaining duration of 7 us may be padded with invalid data to further prevent the unauthorized control channel from being preempted by the same system or different systems within the 7us.
  • the padding information in the target OFDM symbol includes any one of the following: a combination of a WiFi signal preamble and a signal field, or a combination of a WiFi signal preamble, a signal field, and invalid data, and in the target OFDM symbol
  • the padding information is sent after the channel reservation signal in the OFDM symbol, and the length field in the signal field is marked as 0, to prevent the receiver of the channel reservation signal from receiving and parsing the subsequent data according to the length field, thereby mistaking the complete channel reservation signal It is the LAA business data.
  • the padding information in the target OFDM symbol includes any one of the following: a combination of a WiFi signal preamble and a signal field, or a combination of a WiFi signal preamble, a signal field, and invalid data
  • padding information in the target OFDM symbol is in the OFDM
  • the channel reservation signal in the symbol is sent before, and the length field in the signal field is marked as 0, or the remaining duration of the target OFDM symbol after being occupied by the signal preamble and the signal field. Since in this case, the padding information is located before the channel reservation signal, and the length of the length field in the padding information is generally small, the length of the reserved length field is not occupied by the channel reservation signal, so that the channel is not caused.
  • the receiver of the reservation signal misinterprets the complete channel reservation signal as a problem of the LAA service data. Therefore, the length field may be filled with a smaller value. Specifically, the value may be less than or equal to that occupied by the subsequent channel reservation signal. Any value of the duration.
  • the RTS frame or the CTS frame of different modulation and modulation modes can be used in combination according to actual usage, including but not limited to the above examples.
  • the sequence of the RTS frame or the CTS frame may be reserved, and may be generated when the RTS frame or the CTS frame needs to be transmitted. Not limited.
  • the embodiment of the present invention further provides a method for transmitting a channel reservation signal. Specifically, before transmitting a channel reservation signal on an unlicensed channel, the base station first performs sampling rate conversion on the channel reservation signal to obtain a target signal; wherein, the target signal The sampling rate is a sampling rate of the LAA signal; in this case, the base station transmitting the channel reservation signal on the unlicensed channel may include: the base station transmitting the target signal on the unlicensed channel.
  • the channel reservation signal conforms to the WiFi frame format, it has the sampling rate of the WiFi signal; and the sampling rate of the WiFi signal is different from the sampling rate of the LAA signal; taking the system bandwidth of 20 MHz as an example, the sampling rate of the WiFi signal is 20 MHz, LAA The sampling rate of the signal is 30.72 MHz.
  • a set of radio frequency links may be shared in a time division multiplexing manner, and the base station may sample the rate before transmitting the channel reservation signal. The sampling rate converted to the LAA signal. In this way, hardware resources can be saved, thereby reducing costs.
  • sampling rate conversion can be implemented by software.
  • the sample rate conversion is essentially a cascade of primary or multi-stage filters.
  • the sampling rate conversion includes increasing the sampling rate and reducing the sampling rate.
  • the sampling rate is usually implemented by interpolation.
  • the sampling rate is usually reduced by the extraction method.
  • the specific implementation process can refer to the prior art.
  • the base station if the result of the CCA detection is that the unlicensed channel is idle, the base station sends the channel reservation signal on the unlicensed channel, which may include: in the cross-carrier scheduling scenario, if the result of the CCA detection is an unlicensed channel When idle, the base station transmits a channel reservation signal on the last one or more OFDM symbols of the unlicensed channel for carrying control data.
  • one subframe is composed of 14 OFDM symbols; each downlink subframe is divided into two parts, that is, a control area and a data area, the control area is used for transmitting control data, and the data area is used for transmitting service data.
  • the data of the OFDM symbol of the control region is generally 1 to 3.
  • the data of the OFDM symbol of the control region is generally 2 to 4.
  • the cross-carrier scheduling scenario can be understood as: the authorized serving cell uses the authorized channel to send the non- Authorize the control data of the serving cell.
  • the cross-carrier scheduling LAA system has an authorized serving cell and an unlicensed serving cell, and the authorized serving cell uses the authorized channel to communicate with the terminal, and the unlicensed serving cell uses the unlicensed channel to communicate with the terminal. Since the control data of the unlicensed serving cell is transmitted by the authorized serving cell by using the grant channel in the cross-carrier scheduling scenario, the control area of the unlicensed channel is in an idle state, and therefore, the base station can send a channel reservation in the control area of the unlicensed channel. The signal; thus, the resources of the control area of the unlicensed channel are effectively utilized.
  • using the cross-carrier scheduling mechanism provided by this embodiment to transmit a channel reservation signal can also improve spectrum efficiency.
  • Scenario 1 In combination with the foregoing optional embodiment, when a base station sends a second channel reservation signal or a non-first group channel reservation signal in a plurality of sets of channel reservation signals, a subframe in which the second channel reservation signal is located or the non-first group channel reservation The performance of the sub-frame where the signal is located will be degraded.
  • Scenario 2 If the detection result of the CCA is that the time between the unlicensed channel idle time and the start boundary of the next subframe is insufficient to transmit the channel reservation signal, the channel reservation signal needs to be transmitted in the next subframe, which reduces the spectral efficiency. . Therefore, in the two scenarios, using the cross-carrier scheduling mechanism provided by this embodiment to transmit a channel reservation signal can improve spectrum efficiency.
  • the control region includes three OFDM symbols.
  • the channel reservation signal may be transmitted on the third OFDM symbol; optionally, if the control region further includes the fourth OFDM symbol, the channel reservation signal may also be transmitted on the fourth OFDM symbol.
  • FIG. 21 it is a method for transmitting a channel reservation signal according to this embodiment.
  • the base station transmits a channel reservation signal on the third OFDM symbol of one subframe after the time when the CCA detection is that the unlicensed channel is idle.
  • the method may further include: the base station sending a configuration message to the target terminal; wherein the configuration message includes the number r of OFDM symbols carrying the channel reservation signal on the target subframe and the target subframe is used for The number R of OFDM symbols carrying control data to indicate that the target terminal is from the R+r+1 OFDM symbols of the target subframe (OFDM)
  • the symbol index starts from 1 to start receiving/demodulating the service data; wherein the target subframe is a subframe carrying a channel reservation signal, and R and r are integers greater than or equal to 1.
  • the “target terminal” may be any one or more terminals within the coverage of the base station.
  • the target subframe is each subframe that carries a channel reservation signal. If the base station transmits a set of channel reservation signals, the target subframe refers to a subframe after the time when the detection result of the CCA is that the unlicensed channel is idle, for example, in FIG. The subframe n+1.
  • the sending, by the base station, the configuration message to the target terminal may include: the base station transmitting, by using the PCFICH, the number R of OFDM symbols used to carry the control data in the target subframe to the target terminal, and transmitting, by using the PDCCH, the bearer channel reservation signal on the target subframe by using the PDCCH.
  • the number r of OFDM symbols may include: the base station transmitting, by using the PCFICH, the number R of OFDM symbols used to carry the control data in the target subframe to the target terminal, and transmitting, by using the PDCCH, the bearer channel reservation signal on the target subframe by using the PDCCH.
  • one subframe includes two parts, that is, a control area and a data area; therefore, if the base station transmits the number R of OFDM symbols for carrying control data to the target terminal, it indicates that R OFDM symbols are used to carry control data. That is, the service data is carried from the R+1 OFDM symbol, and the target terminal receives/parses the service data from the R+1th OFDM symbol.
  • one subframe is divided into three parts, namely, a control area, a channel reservation area, and a data area; wherein the channel reservation area is used to transmit a channel reservation signal.
  • the base station also needs to send the number r of OFDM symbols carrying the channel reservation signal on the target subframe to the target terminal, so that the base station uses r OFDM symbol bearer channel reservation signals, that is, starting from the R+r+1 OFDM symbols.
  • the target terminal needs to receive/parse the service data from the R+r+1 OFDM symbols.
  • the system signal is a WiFi signal
  • the method may further include: the base station sending an RTS frame to the target terminal, where the receiving MAC address field of the RTS frame is used to mark the MAC of the WiFi chip of the target terminal.
  • the address is such that the target terminal broadcasts a CTS frame, wherein the CTS frame is marked with information for indicating the length of time to be reserved, so that the device that receives the CTS frame does not transmit data for the length of time to be reserved.
  • the NAV field of the RTS frame can mark the total duration and the duration of the RTS frame.
  • the NAV field in the CTS frame may mark the duration associated with the NAV of the RTS frame, wherein the duration is equal to the duration of the NAV flag in the RTS frame minus the short interframe space (SIFS), and subtracted from the CTS. duration.
  • SIFS short interframe space
  • the “target terminal” may be any one or more terminals within the coverage of the base station.
  • the embodiment provides a mechanism for a base station to send an RTS frame to a target terminal.
  • a device (including a terminal, a base station, and the like) around the target terminal can receive the CTS frame. After receiving the CTS frame, the devices do not send within the reserved time period. Data, thereby being able to reduce interference of surrounding devices to the target terminal; thereby improving the communication quality of communication between the base station and the target terminal in the LAA system.
  • FIG. 22 is a schematic structural diagram of a base station 22 according to an embodiment of the present invention.
  • the base station 22 is configured to perform the steps performed by the base station 22 in the method of transmitting a channel reservation signal provided above.
  • the base station 22 may include a module corresponding to the corresponding step.
  • the detecting unit 2201 and the sending unit 2202 may be included.
  • the detecting unit 2201 is configured to detect whether a system signal is received on the unlicensed channel.
  • the sending unit 2202 is configured to send a channel reservation signal on the unlicensed channel to reserve the unlicensed channel.
  • the detecting unit 2201 is further configured to: if it is detected that the system signal is received on the unlicensed channel, perform a clear channel detection CCA; in this case, the sending unit 2202 is specifically configured to: if the CCA As a result of the detection, if the unlicensed channel is idle, a channel reservation signal is transmitted on the unlicensed channel to reserve the unlicensed channel.
  • the sending unit 2202 is configured to: detect, in each detection period, whether a system signal is received on the unlicensed channel; where the detection period includes one Or a plurality of detection durations; in this case, the detecting unit 2201 is specifically configured to: if it is detected that the system signal is received on the unlicensed channel within any one of the detection durations, stop at the detection duration The system signal is detected during the detection period and CCA is performed.
  • the detecting unit 2201 is configured to: when the CCA is performed, in the Cell On/Off mechanism, start CCA in the N subframes before the LAA system to which the base station 22 belongs is in Cell On; The duration of the N subframes is greater than or equal to the maximum duration of one data transmission of the system to which the system signal belongs.
  • the CCA satisfies at least one of the following conditions:
  • Condition 1 The value of the detection threshold of the CCA is less than or equal to d; wherein the d indicates that the base station 22 performs CCA detection on the same system.
  • Condition 2 The detection duration of the CCA is greater than or equal to the detection duration when the base station 22 performs CCA on the same system and the maximum detection duration when the base station 22 performs CCA.
  • Condition 3 The duration of the delay defer in the CCA process is greater than or equal to the maximum of the defer duration when the base station performs CCA on the same system and the defer duration when the CCA is performed on the different system.
  • the sending unit 2202 is specifically configured to: continuously send S channel reservation signals on the unlicensed channel; wherein a reservation field of the sth channel reservation signal is used to mark the s+1th channel a sum of a duration of the reservation signal to the Sth channel reservation signal and a duration to be reserved; wherein 1 ⁇ s ⁇ S, S and s are integers, and the to-be-reserved duration refers to the non- The length of time required to transfer data on the authorized channel.
  • the sending unit 2202 is specifically configured to: send a channel reservation signal on each target OFDM symbol on the unlicensed channel; where the target OFDM symbol refers to an OFDM symbol after the target time
  • the P OFDM symbols starting from the first OFDM symbol, the target time is when the detecting unit 2201 determines that the detection result of the CCA is that the unlicensed channel is idle, and P is an integer greater than or equal to 1.
  • the signal on the target OFDM symbol includes, but is not limited to, the following modes 1-3:
  • the reservation field of the channel reservation signal sent on the pth target OFDM symbol is used to mark the remaining duration of the pth target OFDM symbol occupied by the channel reservation signal; a reserved field of the channel reservation signal sent on the target OFDM symbol is used to mark a sum of a remaining duration of the Pth target OFDM symbol occupied by the channel reservation signal and a duration to be reserved; , 1 ⁇ p ⁇ P, and p is an integer.
  • Mode 2 A reserved field of each of the channel reservation signals sent on each of the target OFDM symbols is used to mark a sum of a remaining duration of the target OFDM symbol occupied by the channel reservation signal and a duration to be reserved.
  • Manner 3 The reserved field of the channel reservation signal sent on the mth target OFDM symbol is used to mark (Pm)* the sum of the duration of the OFDM symbol and the duration to be reserved; wherein, 1 ⁇ m ⁇ P, m is an integer .
  • the system signal is a WiFi signal; any one of the following information on the target OFDM symbol occupied by the channel reservation signal is filled with any one of the following information: a WiFi control frame; a WiFi signal preamble A combination of a code and a signal field; a combination of a WiFi signal preamble, a signal signal field, and invalid data.
  • the padding information in the target OFDM symbol includes any one of the following: a combination of a WiFi signal preamble and a signal field, or a combination of a WiFi signal preamble, a signal field, and invalid data, and the target OFDM symbol
  • the padding information in the OFDM symbol is transmitted after the channel reservation signal, and the length field in the signal field is marked as 0.
  • the padding information in the target OFDM symbol includes any one of the following: a combination of a WiFi signal preamble and a signal field, or a combination of a WiFi signal preamble, a signal field, and invalid data, and the target OFDM symbol
  • the padding information is sent before the channel reservation signal in the OFDM symbol, the length field in the signal field is marked as 0, or the target preamble and the signal are on the target OFDM symbol The remaining duration after the signal field is occupied.
  • the sending unit 2202 is specifically configured to:
  • a modulation order of the data transmitted on the subframe in which the second channel reservation signal is located is less than or a modulation order equal to the data transmitted on the subframe reserved by the first channel reservation signal, where the coding rate of the data transmitted on the subframe in which the second channel reservation signal is located is less than or equal to the first channel reservation signal.
  • the base station 22 may further include: a converting unit 2203, configured to perform sampling rate conversion on the channel reservation signal before the sending unit 2202 transmits the channel reservation signal on the unlicensed channel, Obtaining a target signal; wherein, the sampling rate of the target signal is a sampling rate of the LAA signal; in this case, the sending unit 2202 is specifically configured to: send the target signal on the unlicensed channel.
  • a converting unit 2203 configured to perform sampling rate conversion on the channel reservation signal before the sending unit 2202 transmits the channel reservation signal on the unlicensed channel, Obtaining a target signal; wherein, the sampling rate of the target signal is a sampling rate of the LAA signal; in this case, the sending unit 2202 is specifically configured to: send the target signal on the unlicensed channel.
  • the system signal is a WiFi signal
  • the sending unit 2202 is further configured to: send a request to send a RTS frame to the target terminal, where the received media access control MAC address field of the RTS frame is used to mark the WiFi chip of the target terminal. a MAC address; such that the terminal broadcast clears a CTS frame, wherein the CTS frame marks information indicating a length of time to be reserved, so that the device receiving the CTS frame is within the time period to be reserved Do not send data.
  • the system signal is a WiFi signal; the length of the reservation to be reserved is T; the maximum duration of the reservation of the combination of the WiFi signal preamble and the signal field is a, and the maximum duration of the reservation of the WiFi control frame is b.
  • the sending unit 2201 sends the channel reservation signal on the unlicensed channel, which may include, but is not limited to, any of the following situations:
  • the transmitting unit 2201 transmits a channel reservation signal represented by a combination of a set of WiFi signal preambles and a signal field on the unlicensed channel, or a channel reservation signal represented by a set of WiFi control frames.
  • the sending unit 2201 sends multiple sets of WiFi on the unlicensed channel.
  • the sending unit 2201 transmits, on the unlicensed channel, a channel reservation signal represented by a combination of multiple sets of WiFi signal preambles and signal fields, or a channel reservation signal represented by multiple sets of WiFi control frames, or a group a channel reservation signal represented by a combination of a plurality of sets of WiFi signal preambles and a signal field and a channel reservation signal represented by one or more sets of WiFi control frames.
  • the sending unit 2201 is specifically configured to: in the Cell On/Off mechanism, on the unlicensed channel, the base station sends a channel reservation signal on one or more OFDM symbols before the LAA system to which the UE belongs belongs to the Cell On Or, in the Cell On/Off mechanism, on the unlicensed channel, the base station transmits a channel reservation signal on one or more OFDM symbols starting from Cell On when the LAA system to which the LAA system to which it belongs is at Cell On; or In the Cell On/Off mechanism, on an unlicensed channel, the base station transmits a channel reservation signal on the OFDM symbol of one or more data regions starting with Cell On when the LAA system to which the UE belongs is in Cell On.
  • the sending unit 2201 is specifically configured to: send the channel reservation signal on the last one or more OFDM symbols of the unlicensed channel for carrying the control data.
  • the sending unit 2201 is specifically configured to: if the detection result of the CCA is that the unlicensed channel is idle, and T1 ⁇ T2, delay the T1-T2 duration after the end of the CCA detection, and send the channel reservation signal on the unlicensed channel, The unlicensed channel is reserved; or, if the detection result of the CCA is that the unlicensed channel is idle, and T1 ⁇ T2, the channel reservation signal is transmitted on the unlicensed channel to reserve the unlicensed channel.
  • the T1 is a delay from the uplink transmission to the downlink transmission of the LAA system to which the base station belongs, and is a time required for the base station to send the channel reservation signal to the air interface.
  • the base station 22 in the embodiment of the present invention may correspond to the base station in the method for transmitting a channel reservation signal according to the foregoing embodiment, and in the base station 22 in the embodiment of the present invention.
  • the division and/or function of each module are used to implement the above method flow. For brevity, no further details are provided herein.
  • the base station 22 in the embodiment of the present invention can be used to perform the foregoing method, and therefore, the technical effects that can be obtained are also referred to the foregoing method embodiments, and details are not described herein again.
  • FIG. 24 is a schematic structural diagram of a base station 24 according to an embodiment of the present invention.
  • the base station 24 can include a processor 2401, a memory 2402, a system bus 2403, and a communication interface 2404.
  • the memory 2402 is configured to store computer execution instructions
  • the processor 2401 is coupled to the memory 2402 via the system bus, and when the base station 242 is running, the processor 2401 executes the memory stored in the memory 2403
  • the computer executes instructions to cause the base station 24 to perform any of the methods described above for transmitting a channel reservation signal.
  • the embodiment further provides a storage medium, which may include the memory 1202.
  • the processor 2401 may be a central processing unit (CPU).
  • the processor 2401 can also be another general-purpose processor, a digital signal processing (DSP), an application specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). ) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, and the like.
  • the general purpose processor may be a microprocessor or the processor or any conventional processor or the like.
  • the processor 2401 may be a dedicated processor, and the dedicated processor may include at least one of a baseband processing chip, a radio frequency processing chip, and the like. Further, the dedicated processor may also include a chip having other dedicated processing functions of the base station 24.
  • the memory 2402 can include a volatile memory, such as Such as random access memory (RAM); the memory 2402 may also include non-volatile memory, such as read-only memory (ROM), flash memory ( A flash memory, a hard disk drive (HDD) or a solid-state drive (SSD); the memory 2402 may also include a combination of the above types of memories.
  • RAM random access memory
  • non-volatile memory such as read-only memory (ROM), flash memory ( A flash memory, a hard disk drive (HDD) or a solid-state drive (SSD); the memory 2402 may also include a combination of the above types of memories.
  • the system bus 2403 can include a data bus, a power bus, a control bus, a signal status bus, and the like. For the sake of clarity in the present embodiment, various buses are illustrated as system bus 2403 in FIG.
  • the communication interface 2404 can be specifically a transceiver on the base station 24.
  • the transceiver can be a wireless transceiver.
  • the wireless transceiver can be an antenna or the like of the base station 24.
  • the processor 2401 performs data transmission and reception with the other device, such as the terminal, through the communication interface 2404.
  • each step in any of the foregoing method flows may be implemented by the processor 2401 in hardware form executing a computer-executed instruction in the form of software stored in the memory 2402. To avoid repetition, we will not repeat them here.
  • the base station 24 provided by the embodiment of the present invention can be used to perform the foregoing method, and therefore, the technical effects that can be obtained can be referred to the foregoing method embodiments, and details are not described herein again.
  • the above described device is only illustrated by the division of the above functional modules. In practical applications, the above functions may be assigned differently according to needs.
  • the function module is completed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.
  • the device and the unit described above refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.
  • the disclosed system, apparatus, and method may be implemented in other manners.
  • the device embodiments described above are merely illustrative, for example, the division of the modules or units is only one type of logic
  • the functional division can be implemented in another way.
  • multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.
  • each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.
  • the integrated unit if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium.
  • the technical solution of the present invention which is essential or contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product stored in a storage medium.
  • a number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) or a processor to perform all or part of the steps of the methods described in various embodiments of the present invention.
  • the foregoing storage medium includes: a U disk, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk, and the like, which can store a program code.

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Abstract

本发明公开了一种发送信道预约信号的方法和基站，涉及通信技术领域，用以减少资源的浪费。本发明实施例提供的方法包括：基站检测在非授权信道上是否接收到系统信号；若所述基站检测到在所述非授权信道上接收到所述系统信号，则所述基站在所述非授权信道上发送信道预约信号，以预约所述非授权信道。

Description

一种发送信道预约信号的方法和基站
本申请要求于2015年12月24日提交中国专利局、申请号为PCT/CN2015/098782、发明名称为“一种发送信道预约信号的方法和基站”的PCT专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及通信技术领域，尤其涉及一种发送信道预约信号的方法和基站。
背景技术
辅助授权接入(licensed assisted access，LAA)系统，即非授权长期演进(unlicense-long term evolution，U-LTE)系统，与无线保真(Wireless Fidelity，WiFi)系统共存的关键是有效避免因二者同时占用一个非授权信道，也就是非授权频谱而导致的同频干扰。
LAA系统中的网元包括基站，WiFi系统中的网元包括WiFi接入点(access point，AP)。基站采用载波监听/空闲信道检测(carrier sense/clear channel assessment，CS/CCA)机制来检测当前非授权信道是否被占用，其中，在该机制下，WiFi AP只能检测到信号强度大于或等于检测门限的信号，并且，WiFi AP检测同系统信号(即WiFi信号)和异系统信号(例如LAA信号)时所使用的检测门限不同；以系统带宽为20MHz(兆赫兹)为例，WiFi AP检测WiFi信号时所使用的检测门限是-82dBm，检测LAA信号时所使用的检测门限是-62dBm。如果LAA信号强度在-82dBm～-62dBm范围内，WiFi AP将无法检测到。从而导致当基站在非授权信道上发送信号强度在-82dBm～-62dBm的LAA信号时，WiFi AP不能有效避让该非授权信道，最终二者可能因同时在该非授权信道信道上发送信号而造成同频 干扰。
为了解决上述问题，基站可以在非授权信道上发送信道预约信号，其中，该信道预约信号采样WiFi帧格式。这样，WiFi AP会将该基站所属的LAA系统作为同系统，从而将检测门限设置为-82dBm，因此能够检测到信号强度在-82dBm～-62dBm范围内的LAA信号，从而能够实现当信号强度在-82dBm～-62dBm范围内的LAA信号占用非授权信道时，WiFi AP避让该非授权信道，从而减少同频干扰发生的概率。
在上述发送信道预约信号的过程中，基站在每次需要占用非授权信道时都会发送信道预约信号，这会造成资源的浪费。
发明内容
本发明的实施例提供一种发送信道预约信号的方法和基站，用以减少资源的浪费。
为达到上述目的，本发明的实施例采用如下技术方案：
第一方面，提供一种发送信道预约信号的方法，包括：
基站检测在非授权信道上是否接收到系统信号；
若所述基站检测到在所述非授权信道上接收到所述系统信号，则所述基站在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
本发明实施例提供的发送信道预约信号的方法中，若基站检测到在非授权信道上接收到系统信号，则发送信道预约信号，以预约该非授权信道。与现有技术中在每次需要占用非授权信道之前均发送信道预约信号相比，能够节省一定的资源。
第二方面，提供一种基站，包括：检测单元和发送单元；
所述检测单元，用于检测在非授权信道上是否接收到系统信号；
若所述检测单元检测到在所述非授权信道上接收到所述系统信 号，则发送单元用于在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
由于本发明实施例中的基站可以用于执行上述第一方面中所述的发送信道预约信号的方法，因此其所能获得的技术效果可以参考上述第一方面中基站执行发送信道预约信号的方法时的技术效果，此处不再赘述。
在上述第一方面中，可选的，若所述基站检测到在所述非授权信道上接收到所述系统信号，则所述基站在所述非授权信道上发送信道预约信号，以预约所述非授权信道，可以包括：若所述基站检测到在所述非授权信道上接收到所述系统信号，则所述基站进行空闲信道检测CCA；若所述CCA的检测结果是所述非授权信道空闲，则所述基站在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
相应地，在上述第二方面中，可选的，所述检测单元还可以用于：若检测到在所述非授权信道上接收到所述系统信号，则进行空闲信道检测CCA；所述发送单元具体可以用于：若所述CCA的检测结果是所述非授权信道空闲，则在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
该可选的实现方式与现有技术中的在发送信道预约信号之前不进行任何操作的技术方案相比，能够保证基站在发送信道预约信号时非授权信道空闲，这样，基站所发送的信道预约信号被该系统信号所在的同系统或异系统接收到的概率增加，从而使得达到预约信道和避免同频干扰的目的的概率增加。
在上述第一方面中，可选的，所述基站检测在所述非授权信道上是否接收到系统信号，可以包括：所述基站在每个检测周期内检测在所述非授权信道上是否接收到系统信号；其中，所述检测周期包括一个或多个检测时长；该情况下，若所述基站检测到在所述非授权信道上接收到所述系统信号，则所述基站进行CCA，可以包括：若所述 基站在任意一个所述检测时长内检测到在所述非授权信道上接收到所述系统信号，则停止在该检测时长所属的检测周期内检测所述系统信号，并进行CCA。
相应地，在上述第二方面中，可选的，所述发送单元具体可以用于：在每个检测周期内检测在所述非授权信道上是否接收到系统信号；其中，所述检测周期包括一个或多个检测时长。该情况下，所述检测单元具体可以用于：若在任意一个所述检测时长内检测到在所述非授权信道上接收到所述系统信号，则停止在该检测时长所属的检测周期内检测所述系统信号，并进行CCA。
该可选的实现方式提供了基于大粒度的检测周期和小粒度的检测时长，其中，大粒度的检测周期可以避免错过系统信号的检测，小粒度的检测时长能够使得基站快速地检测到系统信号。
在上述第一方面中，可选的，所述基站进行CCA，可以包括：在Cell On/Off机制中，所述基站在所述基站所属的LAA系统处于Cell On之前的N个子帧开始进行CCA；其中，N个子帧的时长大于或等于所述系统信号所属的系统的一次数据发送的最大持续时长。
相应地，在上述第二方面中，可选的，所述检测单元在执行进行CCA时，具体可以用于：在Cell On/Off机制中，在所述基站所属的LAA系统处于Cell On之前的N个子帧开始进行CCA；其中，N个子帧的时长大于或等于所述系统信号所属的系统的一次数据发送的最大持续时长。
对于Cell On/Off机制而言，Cell On的时长和Cell Off的时长相对固定，因此，Cell On和Cell Off之间的分界点一般是固定不变的。该可选的实现方式改变了Cell On和Cell Off之间的分界点，具体是将基站发送信道预约信号开始的时刻作为新分界点。优选地，当确定CAA的检测结果是信道空闲时立即发送信道预约信号时，是将CAA的检测结果是信道空闲时的时刻作为新分界点。
在第一方面或第二方面中的涉及CCA的任一可选的实现方式中，可选的，该CCA满足以下至少一个条件：条件1、该CCA的检测门限的取值范围小于或等于d；其中，d表示所述基站对同系统进行CCA时的检测门限和对异系统进行CCA时的检测门限的最小值。条件2、CCA的检测时长大于或等于基站对同系统进行CCA时的检测时长和对异系统进行CCA时的检测时长的最大值。条件3、该CCA的defer时长大于或等于基站对同系统进行CCA时的defer时长以及对异系统进行CCA时的defer时长中的最大值。
该可选的实现方式提供了一种增强的CCA，即降低CCA的检测门限和/或延长检测时长的CCA。当系统信号是异系统信号时，CCA的检测门限可以设置的足够低，这样能够得基站能够侦听到发送功率较小的异系统信号。另外，基站延长CCA的检测时长可以提高基站进行CCA的检测精准度。
可选的实现方式1：对于第一方面，所述基站在所述非授权信道上发送信道预约信号，可以包括：所述基站在所述非授权信道上连续发送S个信道预约信号。相应地，对于第二方面，所述发送单元具体可以用于：在所述非授权信道上连续发送S个信道预约信号。其中，第s个信道预约信号的预约字段用于标记所述第s+1个所述信道预约信号至所述第S个所述信道预约信号所占用的时长与待预约时长之和；其中，1≤s≤S，S和s均是整数，所述待预约时长是指在所述非授权信道上传输数据所需使用的时长。
该可选的实现方式1可以基于Cell On/Off机制或LBT机制。该可选的实施例可以理解为：在CCA的检测结果是该非授权信道空闲时，立即发送多个信道预约信号；并且，本实施例中的信道预约信号与OFDM符号无关。
可选的实现方式2：对于上述第一方面，所述基站在所述非授权信道上发送信道预约信号，可以包括：所述基站在所述非授权信道上 的每个目标OFDM符号上发送信道预约信号。相应地，对于上述第二方面，所述发送单元具体可以用于：在所述非授权信道上的每个目标正交频分复用技术OFDM符号上发送信道预约信号。
其中，目标OFDM符号是指从目标时刻所在的OFDM符号后的首个OFDM符号开始的P个OFDM符号，所述目标时刻是指所述检测单元确定所述CCA的检测结果是所述非授权信道空闲的时刻，P是大于或等于1的整数。
该可选的实现方式2可以理解为：在CCA的检测结果是非授权信道空闲时所占用的OFDM符号之后的首个OFDM符号开始发送信道预约信号；并且，信道预约信号的发送是以OFDM符号为时间单位的。
该可选的实现方式1、2与现有技术中的基站在一个子帧的固定位置(例如一个子帧的子帧起始边界或子帧起始边界之后的第3个OFDM符号等)上发送信道预约信号相比，能够避免现有技术中因基站是在固定位置上发送信道预约信号，而导致的从CCA的检测结果是该非授权信道空闲时到该固定的发送信道预约信号的位置的时间段内，非授权信道被同系统或异系统抢占的问题的发生，从而使得基站所在的LAA系统能够快速预约到非授权信道。另外，当S＞1即基站发送多个信道预约信号时，能够提高信道预约信号的接收方对信道预约信号的接收成功率和解码成功率。
在上述可选的实现方式2中，对于上述第一方面或第二方面，若P大于1，则目标OFDM符号上的信道预约信号的预约字段的标记方法包括但不限于以下方式1-3：
方式1、第p个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记所述第p个所述目标OFDM符号上被所述信道预约信号占用后的剩余时长；第P个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记所述第P个所述目标OFDM 符号上被所述信道预约信号占用后的剩余时长与待预约时长之和；其中，1≤p＜P，p是整数。
方式2、每个所述目标OFDM符号上发送的每个所述信道预约信号的预约字段用于标记该目标OFDM符号上被所述信道预约信号占用后的剩余时长与待预约时长之和。
方式3、第m个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记(P-m)*OFDM符号时长与待预约时长之和；其中，1≤m≤P，m是整数。
该方式1、2和3上的每个目标OFDM符号上的信道预约信号均预约了该OFDM符号上被信道预约信号占用之后所剩余的时长，这样，能够避免非授权信道在每个目标OFDM符号的该剩余时长上被同系统或异系统抢占。另外，方式2不需要按照OFDM符号的索引进行预约，实现简单。方式3利用任意一个目标OFDM符号均可以准确预约待预约时长。需要说明的是，具体实现时，在不冲突的情况下，可以根据实际需要对方式1、2和3中的部分特征进行组合，以形成新的标记预约字段的方法，此处不再一一列举。
在上述方式1、2、3中，对于上述第一方面或第二方面，可选的，当系统信号是WiFi信号时；任意一个或多个目标OFDM符号上被信道预约信号还发送填充信息，该填充信息可以包括但不限于以下信息1)至3)中的任一种：1)、WiFi控制帧；2)、WiFi信号前导码和信号signal字段的组合；3)、WiFi信号前导码、信号signal字段和无效数据的组合。
其中，填充信息可以在目标信道预约信号(即上文所述的信道预约信号)之前，也可以在目标信道预约信号之后；目标信道预约信号可以使用WiFi控制帧表示，也可以使用WiFi信号前导码和signal字段的组合表示。
进一步可选的，对于上述第一方面或第二方面，若所述目标 OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal字段和无效数据的组合，且所述目标OFDM符号中的填充信息在所述OFDM符号中的信道预约信号之后发送，所述signal字段中的长度字段标记为0。这样，避免信道预约信号的接收方根据长度字段接收并解析后续数据，从而将完整的信道预约信号误认为是LAA业务数据
另外，对于上述第一方面或第二方面，若所述目标OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal字段和无效数据的组合，且所述目标OFDM符号中的填充信息在所述OFDM符号中的信道预约信号之前发送，所述signal字段中的长度字段标记为0，或该目标OFDM符号上被所述信号前导码和所述signal字段占用后的剩余时长。
在上述第一方面以及第一方面的任一种可选的实现方式中，可选的，所述基站在所述非授权信道上发送信道预约信号，可以包括：所述基站在所述非授权信道上发送第一信道预约信号，并在预设时间段之后，发送第二信道预约信号。相应地，在上述第二方面以及第二方面的任一种可选的实现方式中，可选的，所述发送单元具体可以用于：在所述非授权信道上发送第一信道预约信号，并在预设时间段之后，发送第二信道预约信号。
其中，所述第二信道预约信号所在的子帧上传输的数据的调制阶数小于或等于所述第一信道预约信号所预约的子帧上传输的数据的调制阶数，所述第二信道预约信号所在的子帧上传输的数据的编码率小于或等于所述第一信道预约信号所预约的子帧上传输的数据的编码率。
该可选的实现方式，通过降低调制阶数和编码率，能够提高信道预约信号的接收方对第二信道预约信号的解码成功率。
在上述第一方面以及第一方面的任一种可选的实现方式中，可选 的，所述方法还可以包括：所述基站向目标终端发送配置消息。相应地，在上述第二方面以及第二方面的任一种可选的实现方式中，可选的，所述发送单元还可以用于：向目标终端发送配置消息。
其中，所述配置消息包括目标子帧上承载所述信道预约信号的OFDM符号的数目r和所述目标子帧中用于承载控制数据的OFDM符号的数目R，以指示所述目标终端从所述目标子帧的第R+r+1个OFDM符号开始接收/解调业务数据；其中，所述目标子帧是承载所述信道预约信号的子帧，R和r均是大于或等于1的整数。
该可选的实现方式中，基站需要向目标终端发送目标子帧上承载信道预约信号的OFDM符号的数目r，以说明基站使用了r个OFDM符号承载信道预约信号，即从第R+r+1个OFDM符号开始承载业务数据，则目标终端需要从第R+r+1个OFDM符号开始接收/解析业务数据。
在上述第一方面以及第一方面的任一种可选的实现方式中，可选的，在所述基站在所述非授权信道上发送信道预约信号之前，所述方法还可以包括：所述基站对信道预约信号进行采样率转换，得到目标信号；其中，所述目标信号的采样率是LAA信号的采样率。该情况下，所述基站在所述非授权信道上发送信道预约信号，可以包括：所述基站在所述非授权信道上发送所述目标信号。
相应地，在上述第二方面以及第二方面的任一种可选的实现方式中，可选的，所述基站还可以包括：转换单元，用于在所述发送单元在所述非授权信道上发送信道预约信号之前，对信道预约信号进行采样率转换，得到目标信号；其中，所述目标信号的采样率是LAA信号的采样率。该情况下，所述发送单元具体可以用于：在所述非授权信道上发送所述目标信号。
该可选的实现方式，能够实现LAA信号与信道预约信号的共硬件发送，即LAA信号和信道预约信号可以按照时分复用的方式共用 一套射频链路；这样，能够节约硬件资源，从而降低成本。
在上述第一方面以及第一方面的任一种可选的实现方式中，可选的，所述系统信号是WiFi信号；所述方法还可以包括：所述基站向目标终端发送RTS帧。相应地，在上述第二方面以及第二方面的任一种可选的实现方式中，可选的，所述系统信号是WiFi信号；所述发送单元还可以用于：向目标终端发送请求发送RTS帧。
其中，所述RTS帧的接收媒体访问控制MAC地址字段用于标记所述目标终端的WiFi芯片的MAC地址；以使得所述终端广播清除发送CTS帧，其中，所述CTS帧中标记用于表示待预约时长的信息，进而以使得接收到所述CTS帧的设备在所述待预约时长内不发送数据。
该可选的实现方式提供了一种基站向目标终端发送RTS帧的机制；目标终端周围的设备(包括终端、基站等)能够接收到CTS帧，接收到CTS帧之后，这些设备在待预约时长内不发送数据，从而能够减少周围的设备对目标终端的干扰；从而提高LAA系统中基站与目标终端之间进行通信的通信质量。
在上述第一方面或第一方面的任一种可选的实现方式中，可选的，系统信号是WiFi信号；待预约时长为T；WiFi信号前导码和signal字段的组合所预约的最大时长是a，WiFi控制帧所预约的最大时长是b。该情况下，基站在非授权信道上发送信道预约信号，可以包括但不限于以下几种情况中的任一种：
当T≤a时，基站在该非授权信道上发送一组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或一组WiFi控制帧所表示的信道预约信号。
当a＜T≤b时，基站在该非授权信道上发送多组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或一组WiFi控制帧所表示的信道预约信号。
当T＞b时，基站在该非授权信道上发送多组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或多组WiFi控制帧所表示的信道预约信号，或一组/多组WiFi信号前导码和signal字段的组合所表示的信道预约信号与一组/多组WiFi控制帧所表示的信道预约信号。
相应地，在上述第二方面或第二方面的任一种可选的实现方式中，可选的，系统信号是WiFi信号；待预约时长为T；WiFi信号前导码和signal字段的组合所预约的最大时长是a，WiFi控制帧所预约的最大时长是b。该情况下，发送单元具体用于：
当T≤a时，在该非授权信道上发送一组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或一组WiFi控制帧所表示的信道预约信号。
当a＜T≤b时，在该非授权信道上发送多组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或一组WiFi控制帧所表示的信道预约信号。
当T＞b时，在该非授权信道上发送多组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或多组WiFi控制帧所表示的信道预约信号，或一组/多组WiFi信号前导码和signal字段的组合所表示的信道预约信号与一组/多组WiFi控制帧所表示的信道预约信号。
在上述第一方面中，可选的，基站在非授权信道上发送信道预约信号，可以包括：
在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On之前的1个或多个OFDM符号上发送信道预约信号；或者，
在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On时，在Cell On开始的1个或多个OFDM符号上发送信道预约信号；或者，
在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On时，在Cell On开始的1个或多个数据区域的OFDM符号上发送信道预约信号。
相应地，在上述第二方面中，可选的，发送单元具体可以用于：
在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On之前的1个或多个OFDM符号上发送信道预约信号；或者，
在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On时，在Cell On开始的1个或多个OFDM符号上发送信道预约信号；或者，
在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On时，在Cell On开始的1个或多个数据区域的OFDM符号上发送信道预约信号。
该可选的实施例能够适用于不具备CCA功能的LAA系统进行信道预约的场景中，即在不具备CCA功能的LAA系统中，能够预约非授权信道。另外，无论LAA系统是否具备CCA功能，基站均可以在同系统或异系统不进行高吞吐量的业务的情况下，不进行CCA，而直接利用该可选的实施例预约非授权信道。
在上述第一方面，可选的，若CCA检测的结果是非授权信道空闲，则基站在非授权信道上发送信道预约信号，可以包括：在跨载波调度场景中，若CCA检测的结果是非授权信道空闲，则基站在非授权信道的用于承载控制数据的最后1个或多个OFDM符号上发送信道预约信号。
相应地，在上述第二方面中，可选的，若CCA检测的结果是非授权信道空闲，则发送单元具体用于：在非授权信道的用于承载控制数据的最后1个或多个OFDM符号上发送信道预约信号。
该可选的实现方式有效利用了非授权信道的控制区域的资源。另 外，还能够提高频谱效率。
在上述第一方面中，可选的，若CCA的检测结果是非授权信道空闲，则基站在非授权信道上发送信道预约信号，以预约所述非授权信道，包括：若CCA的检测结果是非授权信道空闲，且T1≥T2，则基站在该CCA检测结束后延迟T1-T2时长，在非授权信道上发送信道预约信号，以预约非授权信道。相应地，在上述第二方面中，可选的，发送单元具体用于：若CCA的检测结果是非授权信道空闲，且T1≥T2，则在该CCA检测结束后，延迟T1-T2时长，在非授权信道上发送信道预约信号，以预约非授权信道。T1是基站所属的LAA系统的上行传输切换到下行传输的时延，T2是所述基站将所述信道预约信号发送至空口所需要的时间。这样，能够保证基站在空口发送信道预约信号时，LAA系统已经由上行传输切换至下行传输。需要说明的是，若LAA系统还未由上行传输切换至下行，基站就发送信道预约信号，则会使得该信道预约信号被破毁掉，从而影响接收端对信道预约信号的解码。
在上述第一方面中，可选的，若CCA的检测结果是非授权信道空闲，则基站在非授权信道上发送信道预约信号，以预约所述非授权信道，包括：若CCA的检测结果是非授权信道空闲，且T1＜T2，则基站在非授权信道上发送信道预约信号，以预约非授权信道。相应地，在上述第二方面中，可选的，发送单元具体用于：若CCA的检测结果是非授权信道空闲，且T1＜T2，则在非授权信道上发送信道预约信号，以预约非授权信道。T1是基站所属的LAA系统的从上行传输切换到下行传输的时延，是所述基站将所述信道预约信号发送至空口所需要的时间。这样，能够避免其他系统抢占该非授权信道。
第三方面，提供一种基站，包括：处理器、存储器和系统总线；所述存储器用于存储计算机执行指令，所述处理器与所述存储器通过所述系统总线连接，当所述基站运行时，所述处理器执行所述存储器 存储的所述计算机执行指令，以使所述基站执行上述第一方面或者第一方面的任一种可选的实现方式提供的任一种发送信道预约信号的方法。
由于本发明实施例中的基站可以用于执行上述第一方面中所述的发送信道预约信号的方法，因此其所能获得的技术效果可以参考上述第一方面中基站执行发送信道预约信号的方法时的技术效果，此处不再赘述。
第四方面，提供一种可读介质，包括计算机执行指令，当基站的处理器执行所述计算机执行指令时，所述基站执行上述发送信道预约信号的方法。
由于本发明实施例提供的可读介质可以执行上述发送信道预约信号的方法，因此其所能获得的技术效果可参考上述方法的实施例，在此不再赘述。
第五方面，提供一种发送信道预约信号的系统，该系统包括基站和多个终端，该基站可以为上述第二方面或第二方面的任一种可选的实现方式中所述的基站。
由于本发明实施例提供的发送信道预约信号的系统包括上述第二方面或第二方面的任一种可选方式中所述的基站，因此其所能获得的技术效果可参考上述基站的实施例，在此不再赘述。
附图说明
图1为本发明实施例所提供的技术方案所适用的一种LAA系统与WiFi系统共存的系统架构示意图；
图2为一种WiFi物理帧结构的示意图；
图3为一种RTS帧结构的示意图；
图4为一种CTS帧结构的示意图；
图5为本发明实施例提供的发送信道预约信号的方法流程图；
图6为本发明实施例提供的发送信道预约信号的示意图一；
图6(a)为本发明实施例提供的一种发送信道预约信号的示意图；
图6(b)为本发明实施例提供的另一种发送信道预约信号的示意图；
图7为本发明实施例提供的一种检测周期P与检测时长T之间的关系的示意图；
图8为本发明实施例提供的一种CCA的触发时机的方法示意图；
图9为本发明实施例提供的发送信道预约信号的示意图二；
图10为本发明实施例提供的发送信道预约信号的示意图三；
图11为本发明实施例提供的发送信道预约信号的示意图四；
图12为本发明实施例提供的确定目标OFDM符号的示意图一；
图13为本发明实施例提供的确定目标OFDM符号的示意图二；
图14为本发明实施例提供的确定目标OFDM符号的示意图三；
图15为本发明实施例提供的确定目标OFDM符号的示意图四；
图16为本发明实施例提供的预约字段的标记方法示意图一；
图17为本发明实施例提供的预约字段的标记方法示意图二；
图18为本发明实施例提供的预约字段的标记方法示意图三；
图19为本发明实施例提供的填充剩余时长的方法示意图一；
图20为本发明实施例提供的填充剩余时长的方法示意图二；
图21为本发明实施例提供的发送信道预约信号的示意图五；
图22为本发明实施例提供的基站的结构示意图一；
图23为本发明实施例提供的基站的结构示意图二；
图24为本发明实施例提供的基站的结构示意图三。
具体实施方式
首先，对本申请中所涉及的部分术语进行解释说明，以方便读者对本申请所提供的技术方案的理解。
1)、同系统，异系统
本发明实施例提供的技术方案的执行主体是基站，因此，本发明实施例中所述的同系统和异系统均是针对该基站所属的LAA系统为参考标准进行说明的；并且“同系统”和“异系统”均是指能够利用非授权信道与终端之间进行通信的系统。具体的，同系统是指LAA系统；异系统是指非LAA系统，例如可以是WiFi系统、无线电定位系统等。其中，一个LAA系统与其同系统是不同的两个LAA系统。其中，终端可以是LAA系统中的终端(user equipment，UE)，或，WiFi系统中的站点(station，STA)等。
2)、同系统信号，异系统信号
同系统信号，是指同系统发送的符合该同系统帧格式的信号，例如，LAA系统发送的LAA信号，具体是LAA系统中的基站发送的LAA信号。异系统信号，是指异系统发送的符合该异系统帧格式的信号，例如，WiFi系统发送的WiFi信号，具体是WiFi系统中的WiFi AP或WiFi STA发送的WiFi信号。其中，下文主要以WiFi AP发送的WiFi信号为例进行说明。
需要说明的是，同系统也可以发送符合某一异系统帧格式的信号，例如LAA系统可以发送信道预约信号，具体是指LAA系统中的基站发送信道预约信号，其中，信道预约信号符合WiFi帧格式。虽然LAA系统可以发送符合WiFi帧格式的信道预约信号，即可以发送WiFi信号；但是，为了进行区分，下文中的WiFi信号，除非特别说明的情况外，其他均是指WiFi系统发送的WiFi信号；而LAA系统发送的WiFi信号直接用信道预约信号表示。
3)、LAA数据，WiFi数据
WiFi数据，是指WiFi系统向终端传输的数据；具体可以包括 WiFi控制数据和WiFi业务数据等。
LAA数据，是指LAA系统向终端传输的数据；具体可以包括LAA控制数据(例如信道预约信号)和LAA业务数据等。
4)、其他术语
本申请中的术语“第一”和“第二”等是用于区别不同的对象，而不是用于描述对象的特定顺序。例如，第一信道预约信号和第二信道预约信号是为了区分不同的信道预约信号，而不是用于描述信道预约信号的特定顺序。
本申请中的术语“多个”除非特别说明的情况外，其他均是指两个或者两个以上。例如多个WIFI AP是指两个或两个以上的WIFI AP。本申请中的术语“系统”和“网络”所代表的含义一致，可互换使用。
本申请中的术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。本申请中的字符“/”，一般表示前后关联对象是一种“或者”的关系。例如，A/B可以理解为A或者B。
其次，说明本发明实施例所适用的场景和网络架构。
本发明实施例所提供的技术方案可以适用于LAA系统与同系统或异系统共存的场景中；其中，主要以适用于LAA系统与WiFi系统)共存的场景为例进行说明。
LAA系统中所涉及的与本发明实施例相关的网元包括基站，WiFi系统中所涉及的与本发明实施例相关的网元包括WIFI AP。另外，本发明实施例中LAA系统或者WiFi系统还包括终端，其中，终端可以连接在基站或WIFI AP上，以与基站或WIFI AP进行通信。
如图1所示，为本发明实施例所提供的技术方案所适用的一种LAA系统与WiFi系统共存的系统架构示意图。其中，图1中示出了多个eNB(基站)与多个WIFI AP之间的部署位置，以及每个eNB 和每个WIFI AP的覆盖范围及其之间的关系。重叠的覆盖范围内出现同频干扰的概率较大，因此，LAA系统和WiFi系统的布局越密集，出现同频干扰的概率越大。需要说明的是，图1只是本发明实施例所适用的一种系统架构的示意图，而非对本发明实施例所适用的场景的限定。
接着，简单说明本发明实施例所涉及的相关技术。
1)、小区打开或关闭(Cell On/Off)机制，先检测后发送(listen before talk，LBT)机制
目前，为了实现LAA系统与WiFi系统共存，LAA系统中的基站在非授权信道上一般采用以下两种机制进行信道检测，一种是基于占空比的检测(或称为信道负载检测)，即Cell On/Off机制；一种是空闲信道检测，即LBT机制。
对于Cell On/Off机制，基站首先在一个Cell On/Off周期内检测一组非授权信道的负载水平，然后选择负载率最低的非授权信道，并根据该负载率最低的非授权信道的占空比检测结果，确定LAA系统的on/off的比例分配，即一个Cell On/Off周期内基站的调度时长；其中，调度时长一般在几十毫秒(ms)级以上。在Cell On/Off机制下，LAA系统可以支持CCA，也可以不支持CCA。
对于LBT机制，基站在每次发送数据包之前，均启动一次CCA，如果CCA的检测结果是无冲突(即非授权信道空闲)，则可以发送数据包；如果CCA的检测结果是冲突(即非授权信道不空闲)，则采用选取随机数的方式进行扩展CCA，直到累计检测到和扩展时长对应的空闲时间后，才发送数据包。例如，若基站选择随机数N，则至少在N*CCA检测时长内再次进行CCA，并基于检测结果确定是否发送数据包，即是否占用非授权信道。
2)、WiFi物理帧结构，即物理层会聚过程协议数据单元(physical layer convergence procedure protocol data unit，PPDU)帧格式。
参见图2，为一种WiFi物理帧结构的示意图。在图2的一种表示方式中，WiFi物理帧结构可以包括：物理层会聚协议(physical layer convergence procedure，PLCP)前导码(preamble)，信号(signal)字段、数据(data)字段。在图2的另一种表示方式中，WiFi物理帧结构可以包括：PLCP前导码，PLCP头(PLCP header)，物理层会聚过程服务数据单元(PLCP service data unit，PSDU)、尾(tail)字段以及填充(pad)字段。
其中，PLCP Header包括：速率(rate)字段、预留(reserved)字段、长度(length)字段、奇偶检验(parity)字段、尾(tail)字段以及服务(service)字段。从调制角度来看，rate字段、reserved字段、长度字段和parity字段，tail字段组成了一个独立的正交频分复用技术(orthogonal frequency division multiplexing，OFDM)符号，记为signal字段。PLCP header的service字段与PSDU，tail字段和可选的pad字段一起，标记为data字段。
需要说明的是，图2中还示出了部分字段所占用的比特数，该部分字段所占用的比特数仅仅作为一种示例，而非对本发明的限定。
3)、WiFi控制帧结构
WiFi控制帧包括请求发送(request to send，RTS)帧和清除发送协议(clear to send，CTS)帧等。需要说明的是，本文中的WiFi控制帧均是指RTS帧或CTS帧。
参见图3，是一种RTS帧结构的示意图。图3所示的RTS帧包括：媒体访问控制(media access control，MAC)头和帧校验序列(frame check sequence，FCS)，其中，MAC头包括：帧控制(frame control)字段、持续时长(duration)字段、接收端地址(receiver address or receiving station address，RA)字段和发送端地址(transmitter address or transmitting station address，TA)字段；这些字段所占用的字节数可以分别是：2、2、6、6、4，即RTS帧格式一般占用20字节。
参见图4，是一种CTS帧结构的示意图。图4所示的CTS帧包括：MAC头和FCS，其中，MAC头包括：frame control字段、duration字段和RA字段；这些字段所占用的字节数可以分别是：2、2、6、4，即CTS帧一般占用14字节。
需要说明的是，由于RTS帧和CTS帧中的Duration字段用于记载网络分配矢量(network allocation vector，NAV)的值，即信道占用时长，因此，具体实现时，可以将duration字段称为NAV字段。
下面将结合本发明实施例中的附图，对本发明实施例所提供的技术方案进行示例性地描述，显然，所描述的实施例仅仅是本发明的一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互组合。
参见图5，为本发明实施例提供的一种发送信道预约信号的方法的流程图。图5所示的方法包括以下步骤S101-S102：
S101：基站检测在非授权信道上是否接收到系统信号。
可选的，步骤S101可以包括：若基站需要占用非授权信道，则该基站在预设时间段内检测在该非授权信道上是否接收到系统信号。可选的，步骤S101可以包括：若基站需要占用非授权信道，则在其所属的LAA系统处于cell off时或CCA时，检测在该非授权信道上是否接收到系统信号。
其中，基站需要占用非授权信道，可以理解为：基站需要通过非授权信道与连接在该基站上的终端之间进行通信。基站在非授权信道上检测是否接收到系统信号，可以理解为：基站在非授权信道对应的频点上检测是否接收到系统信号。系统信号包括同系统信号或异系统信号。
以系统信号是WiFi信号为例，基站可以通过检测WiFi信号前导 码来确定是否接收到WiFi信号。具体的：根据802.11协议可知，WiFi信号前导码是固定的频域序列，因此，基站可以将在非授权信道上所接收到的信号与固定的频域序列相关，如果相关峰存在，则认为存在WiFi信号前导码，即检测到已经接收了WiFi信号。
在一种可选的实现方式中，该方法还可以包括：基站在检测WiFi信号前导码的之后，检测PLCP头中的长度字段，这样，基站可以确定WiFi信号的当前帧的持续时长。这样，在步骤S102中，基站可以在WiFi信号的当前帧结束后发送信道预约信号，以避免在当前帧中的WiFi业务数据对后续的LAA业务数据造成的干扰。
在另一种可选的实现方式中，该方法还可以包括：基站在检测WiFi信号前导码的之后，检测MAC头中的NAV字段。由于在WiFi系统中，一次数据传输过程可能包含多次数据交互过程，例如WIFI AP发送数据包和接收相应的确认字符(acknowledgement，ACK)反馈等交互过程，而NAV字段用于标记一次数据传输过程中的信道占用时长，这样，在步骤S102中，基站可以在WiFi信号的一次数据传输过程结束之后发送信道预约信号，以避免在本次数据传输过程中传输的WiFi业务数据对后续的LAA业务数据造成的干扰。
S102：若该基站检测到在该非授权信道上接收到系统信号，则基站在该非授权信道上发送信道预约信号，以预约该非授权信道。
基站检测到在非授权信道上接收到系统信号，说明：基站所属的LAA系统周围部署了同系统或异系统，即基站周围部署了其他基站或WIFI AP等；并且，当前时刻有同系统或异系统占用该非授权信道。
步骤S102可以包括：若该基站检测到在非授权信道上接收到系统信号，则基站在非授权信道上向该系统信号所属的系统中的网元(例如WIFI AP或另一基站等)发送信道预约信号，以预约该非授权信道。其中，信道预约信号中携带了待预约时长。其中，“待预约时长”是指本次需要发送的LAA业务数据所占用的时长。
信道预约信号符合WiFi帧格式。具体实现时，可以使用WiFi控制帧表示信道预约信号，具体用NAV字段标记部分或全部待预约时长；也可以使用WiFi信号前导码和signal字段的组合表示信道预约信号，具体以长度字段标记部分或全部待预约时长。
在步骤S102之后，该方法还可以包括：基站在发送信道预约信号之后，在待预约时长内向终端发送LAA业务数据。
可选的，在步骤S101之后，该方法还可以包括：若基站在预设时间段内检测在非授权信道上接收到系统信号，则基站可以直接占用该非授权信道，而不需要通过发送信道预约信号来预约该非授权信道。另外，在该情况下，基站还可以首先进行CCA；若CCA的检测结果是该非授权信道空闲，则基站通过发送信道预约信号来预约非授权信道，其具体实现方式可以参考本文中相关的实施例。该可选的实现方式能够避免基站实际上在非授权信道上接收到了系统信号，但因不能成功解析该系统信号，而误认为在非授权信道上没有接收到系统信号，从而造成基站直接占用非授权信道之后，该系统信号所在的系统在该非授权信道上传输的业务数据对LAA业务数据造成的干扰。
需要说明的是，基站所属的LAA系统周围可以部署同系统或异系统，当该LAA系统需要占用非授权信道时，若该非授权信道正在被某一同系统或异系统占用，则该同系统或异系统就会对LAA系统造成同频干扰。该情况下，基站可以在确定该非授权信道被同系统或异系统占用之后，发送信道预约信号，以预约该非授权信道。但是，某些场景下，例如基站所属的LAA系统的周围不存在同系统和异系统，或者，基站所属的LAA系统周围的同系统和异系统因故障等原因长时间不工作等，基站可以直接占用该非授权信道，即不需要发送信道预约信号，就可利用该非授权信道与终端进行通信。
可选的，为了提高信道预约信号的接收方的接收成功率，基站可以采用较低调制方式和较低编码率对信道预约信号进行处理，例如， 802.11中规定的最低调制方式是二进制相移键控(binary phase shift keying，BPSK)，最低编码率是1/2。
本发明实施例提供的发送信道预约信号的方法中，若基站检测到在非授权信道上接收到系统信号，则发送信道预约信号，以预约该非授权信道。与现有技术中在每次需要占用非授权信道之前均发送信道预约信号相比，能够节省一定的资源。
在一种可选的实施例中，系统信号是WiFi信号；待预约时长为T；WiFi信号前导码和signal字段的组合所预约的最大时长是a，WiFi控制帧所预约的最大时长是b；该情况下，基站在非授权信道上发送信道预约信号，可以包括以下几种情况：
当T≤a时，基站在该非授权信道上发送一组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或一组WiFi控制帧所表示的信道预约信号。
当a＜T≤b时，基站在该非授权信道上发送多组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或一组WiFi控制帧所表示的信道预约信号。
当T＞b时，基站在该非授权信道上发送多组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或多组WiFi控制帧所表示的信道预约信号，或一组/多组WiFi信号前导码和signal字段的组合所表示的信道预约信号与一组/多组WiFi控制帧所表示的信道预约信号。
该可选的实施例可以基于Cell On/Off机制或LBT机制。
一组信道预约信号包括1个或多个信道预约信号；当一组信道预约信号包括多个信道预约信号时，该多个信道预约信号可以是连续的多个信道预约信号，也可以是承载在多个连续的OFDM符号上的多个信道预约信号。当一组信道预约信号包括多个信道预约信号时，该多个信道预约信号用于提高信道预约信号的接收方(例如WIFI AP或 其他基站等)的接收成功率以及解码成功率，但是，同一组信道预约信号的目的是为了预约同一段时长，该时长是待预约时长的部分或全部，具体可以参见下文中的示例。
WiFi信号前导码和signal字段的组合使用长度字段预约时长。如图2所示，长度字段占用12bit；根据802.11协议，长度字段的取值范围是0～4095，以系统带宽是20MHz为例，1个OFDM符号长度为4us(微秒)，当RATE字段所指示的调制方式是BPSK，编码率是1/2时，长度字段所指示的时长最大，具体是5.464ms，约为5ms。即发送一组WiFi信号前导码和signal字段的组合，最多可预约约5ms时长。
RTS帧或CTS帧使用NAV字段预约时长。如图3或图4所示，一个Duration字段(即NAV字段)占用16bit，最大可以预约32767us，即约32ms。即发送一组RTS帧或CTS帧，最多可预约约32ms时长。
因此，在该可选的实施例的一种示例中，a＝5ms，b＝32ms。本领域普通技术人员应当理解的是，当RATE字段所指示的调制方式和编码率变化时，长度字段和NAV字段能够预约的时长会随之变化，该情况下，a和b的取值也应当相应变化，对此不再赘述。
在基站发送一组信道预约信号的场景中，该组信道预约信号所预约的时长等于待预约时长。在基站发送多组信道预约信号的场景中，该多组信道预约信号所预约的时长之和等于待预约时长。其中，每组信道预约信号所预约的时长可以相同也可以不相同。另外，每组信道预约信号的类型可以相同也可以不同，例如，假设基站需要发送两组信道预约信号，那么，该两组信道预约信号可以均使用WiFi控制帧表示；也可以均使用WiFi信号前导码和signal字段的组合表示；还可以一组使用WiFi控制帧表示，另一组使用WiFi信号前导码和signal字段的组合表示。
在基站发送多组信道预约信号的场景中，理论上，基站发送前一 组信道预约信号与后一组信道预约信号之间的时间间隔等于该前一组信道预约信号时长，其中，“时间间隔”是指发送前一组信道预约信号的结束时刻至发送后一组信道预约信号的开始时刻之间的时间。也就是说，基站首先发送前一组信道预约信号，然后在该前一组信道预约信号所预约的时长内向终端发送LAA业务数据；接着，发送后一组信道预约信号，然后在该后一组信道预约信号所预约的时长内向终端发送LAA业务数据；以此类推，直至所发送的多组信道预约信号所预约的总时长等于待预约时长。而实际上，为了保证WiFi系统在CCA过程中，能够接收到后一组信道预约信号，一般地，该“时间间隔”可以略小于前一组信道预约信号时长。
示例性的，假设待预约时长是37ms，基站发送两组信道预约信号，并且第1组信道预约信号用WiFi控制帧表示，其所预约的时长是32ms，第2组信道预约信号用WiFi信号前导码和signal字段的组合表示，其所预约的时长是5ms；基站发送第1组信道预约信号与发送第2组信道预约信号之间的时间间隔略小于32ms，如图6所示。其中，图6中的一个阴影矩形可以表示一个信道预约信号，也可以表示一个OFDM符号。图6是基于下述方式3中所述的信道预约信号的预约时长的标记方法进行说明的，基于其他方式的示例与此类似，此处不再一一列出。
需要说明的是，下文中的各实施例均是以基站发送一组信道预约信号为例进行说明的，本领域普通技术人员应当理解，下文所述的实施例通用适用于基站发送多组信道预约信号的场景中。
在一种可选的实施例中，基站在非授权信道上发送信道预约信号，可以包括：基站在非授权信道上发送第一信道预约信号，并在预设时间段之后，发送第二信道预约信号；其中，第二信道预约信号所在的子帧上传输的数据的调制阶数小于或等于第一信道预约信号所预约的子帧上传输的数据的调制阶数，第二信道预约信号所在的子帧 上传输的数据的编码率小于或等于第一信道预约信号所预约的子帧上传输的数据的编码率。该可选的实施例可以适用于以下场景：基站发送完第二信道预约信号之后，该第二信道预约信号所占的子帧上还有剩余时长，基站在该子帧的该剩余时长内调度LAA业务数据。
具体的，基站可以在非授权信道上发送多个第一信道预约信号(可相当于上述的一组信道预约信号)；并在预约时间段(可相当于上述的时间间隔)之后，发送多个第二信道预约信号(可相当于上述的另一组信道预约信号)。
假设一组第一信道预约信号预约了3ms(即3个子帧)，那么，基站在发送完该组第一信道预约信号之后，可以发送3个子帧(包括子帧1、2、3)的LAA业务数据；假设一组第二信道预约信号的发送时刻是2.5ms(即所占的子帧是子帧3)，则在子帧3(具体是子帧3的前半个子帧)上发送的LAA的数据的调制阶数和编码率，可以均小于或等于在第1、2个子帧上发送的LAA业务数据的调制阶数和编码率。例如，第1、2个子帧上发送的LAA的数据的调制阶数是64正交振幅调制(quadrature amplitude modulation，QAM)，编码率为0.93，第3个子帧上发送的LAA的数据的调制阶数是16QAM，编码码率为0.48。
由于直接在物理层用WiFi信号(这里指信道预约信号)覆盖最后一个OFDM符号的物理下行共享信道(physical downlink shared channel，PDSCH)数据，在高阶调制与编码策略(modulation and coding scheme，MCS)下，将导致循环冗余校验码(cyclic redundancy check，CRC)错误。因此，本实施例通过降低调制阶数和编码率，能够提高信道预约信号的接收方对第二信道预约信号的解码成功率。另外，具体实现时，基站可以通过下行控制信息(downlink control infornation，DCI)通知终端各子帧上的数据的MCS(包括调制方式、调制阶数和编码率等)。
在一种可选的实施例中，步骤S102可以包括：若基站检测到在非授权信道上接收到系统信号，则进行CCA；若CCA的检测结果是该非授权信道空闲时，则基站在该非授权信道上发送信道预约信号，以预约该非授权信道。该可选的实施例可以基于Cell On/Off机制或LBT机制。
具体的，当基站使用一组信道预约信号预约非授权信道时，可以在每次发送该组信道预约信号之前均进行CCA。当基站使用多组信道预约信号预约非授权信道时，可以在每次发送一组信道预约信号之前均进行CCA；另外，该情况下，可选的，当基站发送前一组信道预约信号与后一组信道预约信号之间的时间间隔小于该前一组信道预约信号时长时，基站可以只在发送该多组信道预约信号中的首组信道预约信号之前进行CCA。
现有技术中，基站在发送信道预约信号之前不进行任何操作，这样可能会因可能对其造成干扰的系统处于发送状态而不能接收到该信道预约信号，从而使得该信道预约信号的发送没有意义，这不但浪费资源，同时也达不到预约信道和避免同频干扰的目的。与现有技术相比，该可选的实施例能够保证基站在发送信道预约信号时非授权信道空闲，即没有同系统和异系统占用该非授权信道，也就是说，该系统信号所在的同系统或异系统不处于发送状态(即处于接收状态)，这样，基站所发送的信道预约信号被该系统信号所在的同系统或异系统接收到的概率增加，从而使得达到预约信道和避免同频干扰的目的的概率增加。
可选的，T1是基站所属的LAA系统从上行传输切换至下行传输的时延，T1大于或等于0；T2是基站将信道预约信号发送至空口所需要的时间，T2大于或等于0。若CCA的检测结果是非授权信道空闲，则基站在非授权信道上发送信道预约信号，以预约该非授权信道，可以包括：若CCA的检测结果是非授权信道空闲，且T1≥T2，则基 站在该CCA检测结束后，延迟T1-T2时长，在非授权信道上开始发送信道预约信号，以预约非授权信道，如图6(a)所示。这样，能够保证基站在空口发送信道预约信号时，LAA系统已经由上行传输切换至下行传输。或者，若CCA的检测结果是非授权信道空闲，且T1＜T2，则基站在非授权信道上发送信道预约信号，以预约非授权信道。具体的，若CCA的检测结果是非授权信道空闲，且T1＜T2，则基站立即在非授权信道上发送信道预约信号，如图6(b)所示。这样，能够避免其他系统抢占该非授权信道。需要说明的是，该可选的实现方式可以应用于LBT机制或Cell On/Off机制中，另外，图6(a)、图6(b)仅仅表示附图的标号，其与图6之间无从属关系。
其中，基站在CCA检测期间或CCA检测结束之后，需要由上行传输切换至下行传输；其中，上行传输是指基站接收系统信号的过程，下行传输是指基站发送信道预约数据的过程。若信道预约信号是预先存储在基站的存储单元中的，则T2是指基站从该存储单元中取出信道预约信号至该信道预约信号传输至空口时所需要的时间；若信道预约信号是在基站的生成单元中生成的，则T2是指基站从该生成单元中取出信道预约信号至该信道预约信号传输至空口时所需要的时间。另外，本发明实施例对T1和T2的获取方式不进行限定。
本发明实施例所提供的CCA可以是一种增强的CCA，即在现有技术所提供的CCA的基础上进行了一定的改进，该改进可以体现在降低CCA的检测门限和/或延长检测时长和/或延长defer时长上。具体的：当系统信号是异系统信号时，CCA的检测门限可以设置的足够低，以使得基站能够侦听到发送功率较小的异系统信号。在一种可选的实现方式中，CCA的检测门限的取值范围是小于或等于d，其中，d表示基站对同系统进行CCA时的检测门限和对异系统进行CCA时的检测门限的最小值。例如，以系统带宽为20MHz，异系统是WiFi系统为例，基站对同系统的检测门限一般为-52dBm，对WiFi系统的 检测门限一般为-72dBm，则d的取值可以是-82dBm，甚至是-92dBm。本领域普通技术人员应当理解，当系统带宽变化和/或异系统的类型变化时，d的取值也会相应变化。
在本实施例中，基站可以延长CCA的检测时长，从而提高基站进行CCA的检测精准度。具体的：在一种可选的实现方式中，CCA的检测时长大于或等于基站对同系统进行CCA时的检测时长和对异系统进行CCA时的检测时长的最大值。以异系统是WiFi系统为例，该可选的实现方式中的CCA的检测时长大于或等于现有技术中基站对WiFi系统进行CCA时的检测时长，比如，WiFi的defer(延迟)时长为34us或43us，LAA可选的defer时长可以配置为大于或等于43us。需要说明的是，基站执行一次CCA时，首先进行一段时间的延迟(即LAA可选的defer时长)，然后再开始进行CCA。一般地，将从该延迟的起始时刻至输出CCA检测结果的过程称为一次CCA。
在本实施例中，基站可以延长defer的时长，这样，能够延长CCA的检测时长，从而延长CCA的检测时长，以提高基站进行CCA的检测精准度。具体的：在一种可选的实现方式中，本发明实施例中的CCA过程中的defer时长大于或等于基站对同系统进行CCA时的defer时长以及对异系统进行CCA时的defer时长中的最大值。其具体示例可以参考上文，此处不再赘述。
在一种可选的实施例中，在步骤S101中，基站检测在非授权信道上是否接收到系统信号，可以包括：基站在每个检测周期内检测在非授权信道上是否接收到系统信号；其中，一个检测周期包括一个或多个检测时长。该可选的实施例可以基于Cell On/Off机制或LBT机制。
其中，每个检测周期相同，一个检测周期可以包含一个或多个Cell Off时长(即一次Cell Off所占用的时长)或CCA时长；其中，CCA时长是指基站执行一次CCA所占用的时长，CCA时长可以是系 统信号所属的系统的defer时长加上CCA检测过程中计数器减小到0的过程中所需要的时长，以该系统是WiFi系统为例，defer时长是34us或43us。
任意两个检测时长可以相同也可以不同，一个Cell Off时长或一个CCA时长内可以包含一个或多个检测时长；另外，一个检测时长也可以分布在多个Cell Off时长或多个CCA时长内。一般地，每个检测周期内的检测总时长(即各检测时长之和)大于或等于预设阈值，预设阈值的取值越大，检测系统信号的精确度就越高。检测周期和检测时长均可以以秒级为单位，也可以以百毫秒级或毫秒级为单位。
如图7所示，为检测周期P与检测时长T之间的关系的一种示意图。其中，图7中以基站在Cell Off时检测在该非授权信道上是否接收到系统信号为例进行说明，横轴表示时间轴，矩形框所占的时间段表示基站处于Cell On，两个矩形框之间的时间段表示基站处于Cell Off。一个检测周期P包括若干个Cell Off时长，其中的两个Cell Off时长内分别包含时长T1和T2，具体实现时，可以将T1和T2分别作为一个检测时长，也可以将T1+T2作为一个检测时长。
该可选的实施例提供的基于大粒度的检测周期、小粒度的检测时长，其中，大粒度的检测周期可以避免错过系统信号的检测，小粒度的检测时长能够使得基站快速地检测到系统信号。
本发明实施例还提供了一种调整检测周期的大小的技术方案，具体可以根据待预约时长调整检测周期的大小。例如，当系统信号是WiFi信号时，若基站已经获取到了长度字段所指示的时长或NAV字段所指示的时长，则可以根据长度字段所指示的时长或NAV字段所指示的时长调整检测周期的大小，例如，如果长度字段或NAV字段所指示的时长大于检测周期，则可以增加检测周期，并在下一次检测系统信号时启用调整后的检测周期。
在该可选的实施例中，若基站检测到在非授权信道上接收到系统 信号，则基站进行CCA，可以包括：若基站在任意一个检测时长内检测到在非授权信道上接收到系统信号，则停止在该检测时长所属的检测周期内检测系统信号，并进行CCA。
在上述任一种可选的实施例中，基站进行CCA，可以包括：在Cell On/Off机制中，基站在其所属的LAA系统处于Cell On之前的N个子帧开始进行CCA；其中，N个子帧的时长大于或等于该系统信号所属的系统的一次数据发送的最大持续时长。
由于同系统或异系统在每次数据传输过程之间均需要进行信道竞争，因此，在Cell On/Off机制中，当基站在其所属的LAA系统处于Cell On之前的大于或等于系统信号所属的系统的一次数据发送的最大持续时长的时刻开始进行CCA时，一定能够检测到非授权信道空闲的时刻，一旦检测到该时刻，立即开始发送信道预约信号或在下一个OFDM符号开始发送信道预约信号，这样基站能够快速抢占到该非授权信道。需要说明的是，CCA的检测结果是非授权信道空闲的时刻在本申请的附图中均被标记为“空闲时刻”。
对于Cell On/Off机制而言，Cell On的时长和Cell Off的时长在很长一段时间内是固定不变的，只有经过一段时间的占空比测量之后才有可能变化，也就是说，Cell On的时长和Cell Off的时长相对固定，因此，Cell On和Cell Off之间的分界点一般是固定不变的。该实施例改变了Cell On和Cell Off之间的分界点，具体是将基站发送信道预约信号开始的时刻作为新分界点。优选地，当确定CAA的检测结果是信道空闲时立即发送信道预约信号时，是将CAA的检测结果是信道空闲时的时刻作为新分界点。
其中，以异系统是WiFi系统为例，若基站开始进行CCA时，WiFi系统正在进行一次数据传输过程，则该次数据传输过程结束在原分界点之前，该情况下，新分界点在原分界点之前；若基站开始进行CCA时，WiFi系统正处在两次数据传输过程之间，则第2次数据 传输过程的技术时刻在原分界点之后。因此，该可选的实施例，能够使将原分界点提前或滞后。
以系统信号为WiFi信号为例，N个子帧的时长表示WiFi系统的一次数据发送的最大持续时长，即传输机会(transmission opportunity，TXOP)，由于为TXOP配置的最大值一般是8ms，即8个子帧。如图8所示，为该实施例提供的一种CCA的触发时机的示意图。在图8中，原先的Cell On和Cell Off的分界点(即原分界点)是第n-1个子帧与第n个子帧的子帧起始边界，在该分界点之前的8个子帧(即第n-8子帧)开始进行CCA。图8中的阴影矩形表示一组信道预约信号，图8中以新分界点在原分界点之前为例进行说明。
在一种可选的实施例中，基站在非授权信道上发送信道预约信号，可以包括：在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On之前的1个或多个OFDM符号上发送信道预约信号。该1个或多个OFDM符号的持续时长在Cell On时序时长内。可选的，在1个或多个OFDM符号上重复发送多个相同的信道预约信号。
该可选的实施例可以适用于不进行CCA的场景中，也就是说，当基站检测到接收了系统信号之后，可以直接在Cell On之前的1个或多个OFDM符号上发送信道预约信号。该可选的实施例可以改变Cell On和Cell Off之间的分界点，具体的，将分界点提前了该1个或多个OFDM符号。如图9所示，是该可选的实施例提供的一种发送信道预约信号的示意图。其中，图9中，以在Cell On之前的1个OFDM符号上发送信道预约信号为例进行说明，阴影矩形表示一个OFDM符号。原分界点和新分界点如图9所示。
需要说明的是，该可选的实施例能够适用于不具备CCA功能的LAA系统进行信道预约的场景中，即在不具备CCA功能的LAA系统中，能够预约非授权信道。另外，无论LAA系统是否具备CCA功能， 基站均可以在同系统或异系统不进行高吞吐量的业务的情况下，不进行CCA，而直接利用该可选的实施例预约非授权信道。
在一种可选的实施例中，基站在非授权信道上发送信道预约信号，可以包括：在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On时，在Cell On开始的1个或多个OFDM符号上发送信道预约信号。其中，该1个或多个OFDM符号的持续时长在Cell On时序时长内。可选的，在1个或多个OFDM符号上重复发送多个相同的信道预约信号。
该可选的实施例可以适用于不进行CCA的场景中，也就是说，当基站检测到接收了系统信号之后，可以直接在Cell On开始时刻的1个或多个OFDM符号上发送信道预约信号。进一步可选的，在Cell On开始的1个子帧或多个子帧内的每个OFDM符号上发送信道预约信号，这样，能够提高信道预约信号的接收性能；另外，在该进一步可选的实现方式中，可以由LAA系统自动纠正混合自动重传请求(hybrid automatic repeat request，HARQ)的时序问题，或者，LAA系统设置发送信道预约信号的子帧不进行调度。该可选的实施例不会改变Cell On和Cell Off之间的分界点。
在一种可选的实施例中，基站在非授权信道上发送信道预约信号，可以包括：在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On时，在Cell On开始的1个或多个数据区域的OFDM符号上发送信道预约信号。其中，该1个或多个OFDM符号的持续时长在Cell On时序时长内。可选的，在1个或多个OFDM符号上重复发送多个相同的信道预约信号。
该可选的实施例可以适用于不进行CCA的场景中，也就是说，当基站检测到接收了系统信号之后，可以直接在Cell On开始的1个或多个数据区域的OFDM符号上发送信道预约信号，也就是说，控制区域的OFDM符号上可以不发送信道预约信号，这样，能够避免 HARQ的时序问题。进一步可选的，在Cell On开始的1个子帧内或多个子帧内的每个数据区域的OFDM符号上重复发送信道预约信号。该可选的实施例不会改变Cell On和Cell Off之间的分界点。其中，关于控制区域的OFDM符号与数据区域的OFDM符号的解释可以参考下文。
在上述任一种可选的实现方式中，进一步可选的，在Cell On/Off机制中，若Cell On的持续时长大于信道预约信号支持的最大预约时长，则可以在该Cell On持续时长内连续发送1个或连续的多个信道预约信号以以避免其他系统在该Cell On的持续时长内，抢占该非授权信道。例如，若Cell On的持续时长是40ms，信道预约信号支持的最大预约时长是32ms，则在分界点不改变的实现方式中，基站可以在预约了32ms之后，接着再预约8ms，以预约满Cell On的持续时长40ms。需要说明的是，在该可选的实现方式中，可以认为预约信道预约信道支持的最大预约时长的1个或连续的多个信道预约信号是一组信道预约信号，预约Cell On的剩余持续时长的信道预约信号是另一组信道预约信号，该两组信道预约信号的具体实现等内容可以参考本文中的其他示例，此处不再赘述。
在一种可选的实施例中，基站在该非授权信道上发送信道预约信号，可以包括：基站在该非授权信道上连续发送S个信道预约信号；其中，第s个信道预约信号的预约字段用于标记第s+1个信道预约信号至第S个信道预约信号所占用的时长与待预约时长之和；其中，1≤s≤S，S和s均是整数，待预约时长是指在该非授权信道上传输数据所需使用的时长。
该可选的实施例可以基于Cell On/Off机制或LBT机制。该可选的实施例可以理解为：在CCA的检测结果是该非授权信道空闲时，立即发送多个信道预约信号；并且，本实施例中的信道预约信号与OFDM符号无关。
需要说明的是，在该可选的实施例中，基站发送S个信道预约信号的结束时刻可以是下一个子帧起始边界，也可以不是下一个子帧起始边界。S个信道预约信号的调制方式和编码方式可以各不相同，可选的，基站可以通过调整预约信号的调制编码方式调整信道预约信号所占的时长，从而尽量对齐下一个子帧起始边界。
现有技术中，基站是在一个子帧的固定位置上发送信道预约信号，例如在子帧起始边界或子帧起始边界之后的第3个OFDM符号等位置发送信道预约信号。该可选的实施例能够避免现有技术中因基站是在固定位置上发送信道预约信号，而导致的从CCA的检测结果是该非授权信道空闲时到该固定的发送信道预约信号的位置的时间段内，非授权信道被同系统或异系统抢占的问题的发生，从而使得基站所在的LAA系统能够快速预约到非授权信道。另外，当S＞1即基站发送多个信道预约信号时，能够提高信道预约信号的接收方对信道预约信号的接收成功率和解码成功率。
在本实施例中，可以将该多个信道预约信号理解为上述可选实施例所述的一组信道预约信号。当使用WiFi控制帧表示信道预约信号时，信道预约信号的预约字段是指NAV字段；当使用WiFi信号前导码和signal字段的组合表示信道预约信号时，信道预约信号的预约字段是指长度字段。本实施例中，以第s个信道预约信号的预约字段足以标记第s+1个信道预约信号至第S个信道预约信号所占用的时长与待预约时长之和为例进行说明。
将信道预约信号所占用的时长表示为T0，将待预约时长表示为T，那么S个信道预约信号中的每个信道预约信号的预约字段所标记的时长分别如下：第1个信道预约信号的预约字段所标记的时长是(S-1)*T0+T，第2个信道预约信号的预约字段所标记的时长是(S-2)*T0+T……第s个信道预约信号的预约字段所标记的时长是(S-s)*T0+T……第S个信道预约信号的预约字段所标记的时长是T。
如图10所示，为本实施例提供的一种发送信道预约信号的示意图。其中，图10中以S＝8，即基站连续发送8个信道预约信号为例进行说明，图10中的阴影矩形表示信道预约信号。
在一种可选的实施例中，若CCA的检测结果是非授权信道空闲，则基站在该非授权信道上发送信道预约信号，可以包括：基站在非授权信道上的每个目标OFDM符号上发送信道预约信号；其中，目标OFDM符号是指从目标时刻所在的OFDM符号后的首个OFDM符号开始的P个OFDM符号，目标时刻是指基站确定CCA的检测结果是该非授权信道空闲的时刻，P是大于或等于1的整数。
其中，本实施例中认为：当CCA的检测结果是非授权信道空闲的时刻是第i个OFDM符号与第i+1个OFDM符号之间的符号边界时，CCA的检测结果是非授权信道空闲的时刻所在的OFDM符号是第i个OFDM符号；其中，i是整数。另外，由于CCA的检测结果是非授权信道空闲的时刻可能不是OFDM符号边界，该情况下，认为该时刻所在的OFDM符号是不完整的OFDM符号，其他OFDM符号是完整的OFDM符号。
该可选的实施例可以理解为：在CCA的检测结果是非授权信道空闲时所占用的OFDM符号之后的首个OFDM符号开始发送信道预约信号；并且，信道预约信号的发送是以OFDM符号为时间单位的。
本实施例中“多个OFDM符号”可以是一组OFDM符号，其中该组OFDM符号由连续的多个OFDM符号构成；也可以是多组OFDM符号，其中每组OFDM符号是由一个OFDM符号构成或由多个连续的OFDM符号构成，不同组之间相隔一定的时间间隔。其中该时间间隔的相关解释可以参考上文相关实施例，此处不再赘述，
如图11所示，为本实施例提供的一种发送信道预约信号的示意图，其中，图11中以系统信号是WiFi信号为例进行说明，并且，目标OFDM符号是多个连续的OFDM符号，每个目标OFDM符号上发 送一个信道预约信号。图11中的每个白色矩形表示一个OFDM符号，一个子帧由14个OFDM符号构成，部分白色矩形上覆盖有阴影矩形，阴影矩形表示信道预约信号，由图11可知，一个信道预约信号不足以填满一个OFDM符号。
下面说明一个信道与预约信号不足以填满一个OFDM符号的理由：在LAA系统中，对于正常循环前缀(cyclic prefix，CP)，LAA系统中的每个OFDM符号所占用的时长约71us，其中，每个时隙的第1个OFDM符号所占用的时长约71.875us，每个时隙的非第1个OFDM符号所占用的时长约71.35us。对于扩展CP，LAA系统中的每个OFDM符号所占用的时长约83.33us。下文中均以一个添加正常CP的OFDM符号所占用的时长为71us，一个添加扩展CP的OFDM符号所占用的时长为83us为例进行说明。
当一个WiFi控制帧中的RATE字段所指示的调制方式和编码率不同时，该WiFi控制帧所占用的时长不同；其中，当调制方式是BPSK，编码率是
Figure PCTCN2016073701-appb-000001
时，RTS帧和CTS帧所占用的时长均最大，分别是52us和44us。因此，使用WiFi控制帧表示信道预约信号时，一个信道预约信号所占用的时长的最大值是52us或44us。
另外，由于WiFi信号前导码所占用的时长是16us，signal字段占用WiFi系统的1个OFDM符号，即4us，因此，使用WiFi信号前导码和signal字段的组合表示信道预约信号时，一个信道预约信号所占用的时长是20us。因此，无论使用WiFi控制帧表示信道预约信号，还是使用WiFi信号前导码和signal字段的组合表示信道预约信号，一个信道预约信号均不足以填满一个OFDM符号。
具体实现时，发送信道预约信号的子帧上可以发送LAA数据LAA业务数据，也可以不发送LAA数据LAA业务数据。基于在信道预约信号所在的子帧上不发送LAA数据LAA业务数据，下面列举几 种确定目标OFDM符号的方法：
若从CCA的检测结果是该非授权信道空闲时所占用的OFDM符号之后的首个OFDM符号开始至下一个子帧起始边界之间包含多个完整的OFDM符号，则基站可以将该多个OFDM符号作为目标OFDM符号，如图12所示。
若从CCA的检测结果是该非授权信道空闲时所占用的OFDM符号之后的首个OFDM符号开始至下一个子帧起始边界之间仅包含1个完整的OFDM符号，则将该OFDM符号作为目标OFDM符号，或将该OFDM符号和下个子帧均作为目标OFDM符号，如图13所示。
若从CCA的检测结果是该非授权信道空闲时所占用的OFDM符号之后的首个OFDM符号开始至下一个子帧起始边界之间没有完整的OFDM符号，则将下一个子帧中的OFDM符号作为目标OFDM符号，如图14所示。
其中，图12-14中的每个矩形表示一个OFDM符号，每个阴影矩形表示一个目标OFDM符号。图12-14所示的确定OFDM符号的方法均是以最后一个目标OFDM符号是某个子帧起始边界为例进行说明的，具体实现时不限于此，例如，基站可以将从CCA的检测结果是非授权信道空闲时所占用的OFDM符号之后的首个OFDM符号开始的固定数量个OFDM符号作为目标OFDM符号。
在一种可选的实现方式中，多个OFDM符号是连续的多个OFDM符号，即：目标OFDM符号是连续的多个OFDM符号。以图16所示的目标OFDM符号为例进行说明，在图15中，基站在进行CCA的过程中，在子帧n中的OFDM符号2(以0为子帧内起始符号索引)时的CCA的检测结果是该非授权信道空闲，该情况下，目标OFDM符号可以是子帧n中的OFDM符号3～13。下述图16-19的示例中，均以系统信号是WiFi信号，一个RTS帧所占用的时长是52us，待预约时长是3ms为例进行说明。
下面说明信道预约信号的预约字段的几种不同的标记方式：
方式1：第p个目标OFDM符号上发送的信道预约信号的预约字段用于标记第p个目标OFDM符号上被信道预约信号占用后的剩余时长；第P个目标OFDM符号上发送的信道预约信号的预约字段用于标记第P个目标OFDM符号上被信道预约信号占用后的剩余时长与待预约时长之和；其中，1≤p＜P，p是整数。
该方式1可以理解为按照目标OFDM符号的索引进行预约，也就是说，不同的目标OFDM符号上发送的信道预约信号所预约的时长不同，具体的：非最后一个OFDM符号与最后一个OFDM符号上发送的信道预约信号所预约的时长不同。
该方式1中，在每个目标OFDM符号上发送的信道预约信号的预约字段上均标记目标OFDM符号上被信道预约信号占用后的剩余时长，也就是说，每个目标OFDM符号均会预约该剩余时长，这样能够避免非授权信道在每个目标OFDM符号的该剩余时长上被同系统或异系统抢占。并且，该方式1能够利用最后一个目标OFDM符号上发送的信道预约信号准确地预约待预约时长。在该方式1中，信道预约信号的接收方需要接收并解析最后一个目标OFDM符号上发送的信道预约信号之后，才能根据待预约时长避让该非授权信道。
基于图15，当使用RTS帧表示信道预约信号时，对于添加正常CP的目标OFDM来说，一个目标OFDM符号上被RTS帧占用后的剩余时长是71us-52us＝19us；这样，OFDM符号3～12上的RTS帧中的NAV字段标记为19us，OFDM符号13上的RTS帧中的NAV字段标记为19us+3ms，如图16所示。
方式2：每个目标OFDM符号上发送的每个信道预约信号的预约字段用于标记该目标OFDM符号上被信道预约信号占用后的剩余时长与待预约时长之和。
该方式2可以理解为统一预约，其中，不同的OFDM符号上发 送的信道预约信号所预约的时长相同，因此不需要按照OFDM符号的索引进行预约，实现简单；另外，能够避免非授权信道在每个OFDM符号的该剩余时长上被同系统或异系统抢占。
该方式2中，在每个目标OFDM符号上发送的信道预约信号的预约字段上均标记目标OFDM符号上被信道预约信号占用后的剩余时长与待预约时长之和，这样，当信道预约信号的接收方接收并成功解析了任意一个目标OFDM符号上发送的信道预约信号之后，可不再接收和/或不再解析其他目标OFDM符号上发送的信道预约信号；并且，该接收方成功解析了最后一个目标OFDM符号之后，可以得到准确的待预约时长。
基于图15，当使用RTS帧表示信道预约信号时，对于添加正常CP的目标OFDM来说，一个目标OFDM符号上被RTS帧占用后的剩余时长是19us；这样，OFDM符号3～13上的RTS帧中的NAV字段标记为19us+3ms，如图17所示。
方式3：第m个目标OFDM符号上发送的信道预约信号的预约字段用于标记(P-m)*OFDM符号时长与待预约时长之和；其中，1≤m≤P，m是整数。
该方式3可以理解为统一预约，其中，不同目标OFDM符号上发送的信道预约信号所预约的时长不同，因此，需要按照OFDM符号的索引进行预约；但是不同目标OFDM符号上发送的信道预约信号所预约的时长遵循相同的规则，实现简单。另外，能够避免非授权信道在每个OFDM符号的该剩余时长上被同系统或异系统抢占。并且，由于任意一个目标OFDM符号均预约了从该目标OFDM符号开始时刻至LAA业务数据的结束时刻(其中，LAA业务数据的传输时间段即是待预约时长)之间的时间段，因此，任意一个目标OFDM符号均可以准确预约待预约时长。
该方式3中，当信道预约信号的接收方接收并成功解析了任意一 个目标OFDM符号上发送的信道预约信号之后，即可不再接收和/或不再解析其他目标OFDM符号上发送的信道预约信号；并且，无论接收方成功解析的是任意一个目标OFDM符号，均可以得到准确的待预约时长。
基于图15，OFDM符号3是第1个目标OFDM符号，依次类推。当使用RTS帧表示信道预约信号时，对于添加正常CP的目标OFDM来说，OFDM符号3(即第1个目标OFDM符号)上的RTS帧中的NAV字段标记为(11-1)×71us+3ms，OFDM符号4(即第2个目标OFDM符号)上的RTS帧中的NAV字段标记为(11-2)×71us+3ms，依次类推，OFDM符号13(即第11个目标OFDM符号)上的RTS帧中的NAV字段标记为3ms，如图18所示。
另外，具体实现时，上述方式1至3中的部分特征还可以组合使用，例如：方式1、3的组合，或方式2、3的组合可以构成方式4。
方式4：将所有目标OFDM符号分为两部分，前一部分的每个目标OFDM符号遵循方式1中的非最后一个目标OFDM符号上的信道预约信号的标记规则，或按照方式2中的各目标OFDM符号上的信道预约信号的标记规则；后一部分的每个目标OFDM符号遵循方式3中的信道预约信号的标记规则。其中，本发明实施例对将所有目标OFDM符号分为两部分的分界点不进行限定。
与方式1相比，在方式1、3的组合构成的方式4中，信道预约信号的接收方只要接收到后一部分的任意一个目标OFDM符号即可正确解析待预约时长，因此能够提高接收性能。与方式2相比，在方式2、3的组合构成的方式4中，信道预约信号的接收方只要接收到后一部分的任意一个目标OFDM符号即可正确预约待预约时长，因此能够提高所预约的待预约时长的准确度。
基于图15，假设将OFDM符号3～11作为前一部分，将OFDM符号12～13作为后一部分。当使用RTS帧表示信道预约信号时，对 于添加正常CP的目标OFDM来说，OFDM符号3～11上的RTS帧中的NAV字段标记为19us，或19us+3ms；OFDM符号12上的RTS帧中的NAV字段标记为71us+3ms，OFDM符号13上的RTS帧中的NAV字段标记为3ms。
需要说明的是，上述方式1～4还可以有其他的组合方式，此处不再一一列举。另外，在上述方式1～4任一种，对于添加扩展CP的目标OFDM符号来说，在该OFDM符号上发送RTS帧所表示的信道预约信号的NAV所标记的时长与此类似；并且，当使用CTS帧表示信道预约信号，或使用WiFi信号前导码和signal字段的组合表示信道预约信号时，目标OFDM符号上的信道预约信号的预约字段所标记的时长与此类似；在此不再一一赘述。
基于上述所提供的将信道预约信号承载在OFDM符号上的任一种实施例以及任一种可选的实现方式来说，可选的，当系统信号是WiFi信号时；基站任意一个或多个目标OFDM符号上被信道预约信号(下文中称为“目标信道预约信号”)占用后的剩余时长中还发送填充信息，该填充信息可以包括但不限于以下信息1)至3)中的任一种。
需要说明的是，填充信息可以在目标信道预约信号之前，也可以在目标信道预约信号之后；目标信道预约信号可以使用WiFi控制帧表示，也可以使用WiFi信号前导码和signal字段的组合表示。
1)、WiFi控制帧
当目标信道预约信号使用WiFi信号前导码和signal字段的组合表示时，所填充的WiFi控制帧可以是RTS帧，也可以是CTS帧。
当目标信道预约信号使用WiFi控制帧表示时，将该WiFi控制帧称为第一WiFi控制帧，将所填充的WiFi帧称为第二WiFi控制帧。那么，第一WiFi控制帧与第二WiFi控制帧可以是同类型的WiFi控制帧，也可以是不同类型的WiFi控制帧；例如，无论第一WiFi帧是 RTS帧还是CTS帧，第二WiFi帧均可以是RTS帧或CTS帧。另外，第一WiFi帧与第二WiFi帧的调制方式和编码率可以相同也可以不相同。
示例1：当调制方式是BPSK，编码率是3/4时，一个RTS帧(即第一WiFi控制帧)所占的时长是44us；基于上述方式1，对于添加正常CP的目标OFDM来说，一个目标OFDM符号上被该RTS帧占用后的剩余时长是71us-44us＝27us；这样，OFDM符号3～12上的RTS帧中的NAV字段标记为27us，OFDM符号13上的RTS帧中的NAV字段标记为27us+3ms。
当调制方式是64-QAM，编码率是2/3时，一个RTS帧(即第二WiFi控制帧)所占的时长是24us；基于示例1，在该可选的实现方式中，可以将该第二WiFi控制帧填充至目标OFDM符号上发送第一WiFi控制帧之后的剩余时长(即27us)内，填充后，该目标OFDM符号上的剩余时长是27-24＝3us，该情况下，可以将该第二WiFi控制帧的NAV字段标记为3us，如图19所示，以避免非授权控制信道在该3us内被同系统或异系统抢占。
2)、WiFi信号前导码和signal字段的组合
由于WiFi信号前导码和signal字段的组合所占的时长是20us，因此，基于上述示例1，在该可选的实现方式中，可以将WiFi信号前导码和signal字段填充至目标OFDM符号上发送第一WiFi控制帧之后的剩余时长(即27us)内，如图20所示，以避免非授权控制信道在该7us内被同系统或异系统抢占。
3)、WiFi信号前导码、signal字段和无效数据的组合。
基于图20的示例，可以将7us的剩余时长上填充上无效数据，以进一步避免非授权控制信道在该7us内被同系统或异系统抢占。
需要说明的是，图19-20均以方式1所示的示例中的OFDM符号3～12为例进行说明，OFDM符号13的剩余时长的填充方式与此类似， 此处不再赘述。另外，上述方式1～方式4中的任一种可选的实现方式中的OFDM符号的剩余时长的填充方式与此类似，此处不再一一赘述。
进一步可选的，若目标OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal字段和无效数据的组合，且目标OFDM符号中的填充信息在该OFDM符号中的信道预约信号之后发送，signal字段中的长度字段标记为0，以避免信道预约信号的接收方根据长度字段接收并解析后续数据，从而将完整的信道预约信号误认为是LAA业务数据。
若目标OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal字段和无效数据的组合，且目标OFDM符号中的填充信息在该OFDM符号中的信道预约信号之前发送，signal字段中的长度字段标记为0，或该目标OFDM符号上被信号前导码和signal字段占用后的剩余时长。由于该情况下，填充信息位于信道预约信号之前，并且填充信息中的长度字段所预约的时长一般较小，因此，长度字段所预约的时长不会被信道预约信号所占用，从而不会造成信道预约信号的接收方将完整的信道预约信号误认为是LAA业务数据的问题，因此，长度字段可以填充一个较小的值，具体的，该值可以是小于或等于后续的信道预约信号所占用的时长的任一值。
需要说明的是，上述任一可选的实施例或实现方式中所涉及的所有不同NAV，不同调制调制方式的RTS帧或CTS帧，以及RTS帧或CTS帧在OFDM符号中的位置等，都可以根据实际使用情况进行组合使用，包括但不限于上述示例。并且，由于调制方式和编码率可以有限列举，因此，所涉及的RTS帧或CTS帧的序列可以预约设置好，当然也可以在需要发送RTS帧或CTS帧时再生成，本发明实施例对此不进行限定。
本发明实施例还提供了一种发送信道预约信号的方法，具体的：基站在非授权信道上发送信道预约信号之前，首先对信道预约信号进行采样率转换，得到目标信号；其中，目标信号的采样率是LAA信号的采样率；该情况下，基站在非授权信道上发送信道预约信号，可以包括：基站在非授权信道上发送目标信号。
由于信道预约信号符合WiFi帧格式，因此，其具有WiFi信号的采样率；而WiFi信号的采样率与LAA信号的采样率不同；以系统带宽是20MHz为例，WiFi信号的采样率是20MHz，LAA信号的采样率是30.72MHz。为了实现LAA信号与信道预约信号共硬件发送，具体的，为了实现LAA信号和信道预约信号可以按照时分复用的方式共用一套射频链路，基站可以在发送信道预约信号之前，将其采样率转化为LAA信号的采样率。这样，能够节约硬件资源，从而降低成本。
其中，采样率转化的过程可以使用软件实现。采样率转换实质上是一级滤波器或多级滤波器的级联。采样率转换包括提高采样率和降低采样率两种，提高采样率通常采用插值的方法实现，降低采样率通常采用抽取的方法实现。其具体实现过程可以参考现有技术。
在一种可选的实施例中，若CCA检测的结果是非授权信道空闲，则基站在非授权信道上发送信道预约信号，可以包括：在跨载波调度场景中，若CCA检测的结果是非授权信道空闲，则基站在非授权信道的用于承载控制数据的最后1个或多个OFDM符号上发送信道预约信号。
其中，一个子帧由14个OFDM符号构成；每个下行子帧被分成2个部分，即控制区域和数据区域，控制区域用于传输控制数据，数据区域用于传输业务数据。对于带宽较大的系统，控制区域的OFDM符号的数据一般是1～3个；对比带宽较小的系统，控制区域的OFDM符号的数据一般是2～4个。
跨载波调度场景可以理解为：授权服务小区利用授权信道发送非 授权服务小区的控制数据。其中，跨载波调度LAA系统存在授权服务小区和非授权服务小区，授权服务小区利用授权信道与终端进行通信，非授权服务小区利用非授权信道与终端进行通信。由于在跨载波调度场景中，非授权服务小区的控制数据由授权服务小区利用授权信道进行发送，因此非授权信道的控制区域处于空闲状态，因此，基站可以在非授权信道的控制区域发送信道预约信号；这样，有效利用了非授权信道的控制区域的资源。另外，在以下场景下，利用本实施例提供的跨载波调度机制发送信道预约信号还能够提高频谱效率。
场景1：结合上述可选的实施例，基站发送第二信道预约信号或多组信道预约信号中的非首组信道预约信号时，第二信道预约信号所在的子帧或该非首组信道预约信号所在的子帧的性能会降低。场景2：如果CCA的检测结果是非授权信道空闲的时刻至下一个子帧起始边界之间的时长不足以发送信道预约信号，则需要在下一个子帧内发送信道预约信号，这会降低频谱效率。因此，在该两种场景中使用本实施例提供的跨载波调度机制发送信道预约信号，能够提高频谱效率。
具体的，考虑到子帧的第1个OFDM符号上会承载导频数据，且在4天线端口发送时，第2个OFDM符号也存在导频数据，因此，假设控制区域包括3个OFDM符号，则可以在第3个OFDM符号上发送信道预约信号；可选的，若控制区域还包括第4个OFDM符号，则还可以在第4个OFDM符号上发送信道预约信号。如图21所示，是本实施例提供的一种发送信道预约信号的方法。其中，基站在CCA检测的结果是非授权信道空闲的时刻之后的一个子帧的第3个OFDM符号上发送信道预约信号。
在一种可选的实施例中，该方法还可以包括：基站向目标终端发送配置消息；其中，配置消息包括目标子帧上承载信道预约信号的OFDM符号的数目r和目标子帧中用于承载控制数据的OFDM符号的数目R，以指示目标终端从目标子帧的第R+r+1个OFDM符号(OFDM 符号索引从1开始)开始接收/解调业务数据；其中，目标子帧是承载信道预约信号的子帧，R和r均是大于或等于1的整数。
其中，“目标终端”可以是该基站的覆盖范围内的任意一个或多个终端。目标子帧是承载信道预约信号的每个子帧；其中，若基站发送一组信道预约信号，则目标子帧是指CCA的检测结果是非授权信道空闲的时刻之后的一个子帧，例如图21中的子帧n+1。
基站向目标终端发送配置消息，可以包括：基站通过PCFICH向目标终端发送目标子帧中用于承载控制数据的OFDM符号的数目R，以及通过PDCCH向目标终端发送目标子帧上承载信道预约信号的OFDM符号的数目r。
现有技术中，一个子帧包括2个部分，即控制区域和数据区域；所以，若基站向目标终端发送用于承载控制数据的OFDM符号的数目R，说明使用了R个OFDM符号承载控制数据，即从第R+1个OFDM符号开始承载业务数据，则目标终端从第R+1个OFDM符号开始接收/解析业务数据。在本实施例中，将一个子帧分为了3个部分，即控制区域、信道预约区域和数据区域；其中，信道预约区域用于发送信道预约信号。所以，基站还需要向目标终端发送目标子帧上承载信道预约信号的OFDM符号的数目r，以说明基站使用了r个OFDM符号承载信道预约信号，即从第R+r+1个OFDM符号开始承载业务数据，则目标终端需要从第R+r+1个OFDM符号开始接收/解析业务数据。
在一种可选的是实施例中，系统信号是WiFi信号，该方法还可以包括：基站向目标终端发送RTS帧，其中，RTS帧的接收MAC地址字段用于标记目标终端的WiFi芯片的MAC地址；以使得目标终端广播CTS帧，其中，CTS帧中标记有用于表示待预约时长的信息，进而以使得接收到CTS帧的设备在待预约时长内不发送数据。
具体的，RTS帧的NAV字段可以标记总时长与RTS帧所占时长 之差，其中，该总时长是指从CCA的检测结果是非授权信道空闲的时刻开始至LAA业务数据传输结束的时刻之间的时间段，其中包括待预约时长，即LAA业务数据的传输时长；CTS帧中的NAV字段可以标记与RTS帧的NAV相关的时长，其中，该时长等于RTS帧中NAV标记的时长减去短的帧间隔(short interframe space，SIFS)，再减去CTS之后得到的时长。
其中，“目标终端”可以是基站的覆盖范围内的任意一个或多个终端。本实施例提供了一种基站向目标终端发送RTS帧的机制；目标终端周围的设备(包括终端、基站等)能够接收到CTS帧，接收到CTS帧之后，这些设备在待预约时长内不发送数据，从而能够减少周围的设备对目标终端的干扰；从而提高LAA系统中基站与目标终端之间进行通信的通信质量。
参见图22，为本发明实施例提供一种基站22的结构示意图。该基站22用于执行上述提供的发送信道预约信号的方法中的基站22所执行的步骤。基站22可以包括相应步骤所对应的模块，示例的，可以包括：检测单元2201和发送单元2202。
检测单元2201，用于检测在非授权信道上是否接收到系统信号。
若所述检测单元2201检测到在所述非授权信道上接收到所述系统信号，则发送单元2202用于在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
可选的，检测单元2201还用于：若检测到在所述非授权信道上接收到所述系统信号，则进行空闲信道检测CCA；该情况下，发送单元2202具体用于：若所述CCA的检测结果是所述非授权信道空闲，则在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
可选的，发送单元2202具体用于：在每个检测周期内检测在所述非授权信道上是否接收到系统信号；其中，所述检测周期包括一个 或多个检测时长；该情况下，检测单元2201具体用于：若在任意一个所述检测时长内检测到在所述非授权信道上接收到所述系统信号，则停止在该检测时长所属的检测周期内检测所述系统信号，并进行CCA。
可选的，所述检测单元2201在执行进行CCA时，具体用于：在Cell On/Off机制中，在所述基站22所属的LAA系统处于Cell On之前的N个子帧开始进行CCA；其中，所述N个子帧的时长大于或等于所述系统信号所属的系统的一次数据发送的最大持续时长。
可选的，所述CCA满足以下至少一个条件：条件1:、所述CCA的检测门限的取值范围小于或等于d；其中，所述d表示所述基站22对同系统进行CCA时的检测门限和对异系统进行CCA时的检测门限的最小值。条件2、所述CCA的检测时长大于或等于所述基站22对同系统进行CCA时的检测时长和对异系统进行CCA时的检测时长的最大值。条件3、所述CCA过程中的时延defer时长大于或等于所述基站对同系统进行CCA时的defer时长以及对异系统进行CCA时的defer时长中的最大值。
可选的，发送单元2202具体用于：在所述非授权信道上连续发送S个信道预约信号；其中，第s个信道预约信号的预约字段用于标记所述第s+1个所述信道预约信号至所述第S个所述信道预约信号所占用的时长与待预约时长之和；其中，1≤s≤S，S和s均是整数，所述待预约时长是指在所述非授权信道上传输数据所需使用的时长。
可选的，所述发送单元2202具体用于：在所述非授权信道上的每个目标OFDM符号上发送信道预约信号；其中，所述目标OFDM符号是指从目标时刻所在的OFDM符号后的首个OFDM符号开始的P个OFDM符号，所述目标时刻是指所述检测单元2201确定所述CCA的检测结果是所述非授权信道空闲的时刻，P是大于或等于1的整数。
在该可选的实现方式中，若P大于1，则目标OFDM符号上的信 道预约信号的预约字段的标记方法包括但不限于以下方式1-3：
方式1、第p个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记所述第p个所述目标OFDM符号上被所述信道预约信号占用后的剩余时长；第P个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记所述第P个所述目标OFDM符号上被所述信道预约信号占用后的剩余时长与待预约时长之和；其中，1≤p＜P，p是整数。
方式2、每个所述目标OFDM符号上发送的每个所述信道预约信号的预约字段用于标记该目标OFDM符号上被所述信道预约信号占用后的剩余时长与待预约时长之和。
方式3、第m个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记(P-m)*OFDM符号时长与待预约时长之和；其中，1≤m≤P，m是整数。
进一步可选的，系统信号是WiFi信号；任意一个或多个所述目标OFDM符号上被所述信道预约信号占用后的剩余时长中填充以下信息中的任一种：WiFi控制帧；WiFi信号前导码和信号signal字段的组合；WiFi信号前导码、信号signal字段和无效数据的组合。
具体的，若所述目标OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal字段和无效数据的组合，且所述目标OFDM符号中的填充信息在该OFDM符号中的信道预约信号之后发送，所述signal字段中的长度字段标记为0。
或者，若所述目标OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal字段和无效数据的组合，且所述目标OFDM符号中的填充信息在所述OFDM符号中的信道预约信号之前发送，所述signal字段中的长度字段标记为0，或该目标OFDM符号上被所述信号前导码和所述 signal字段占用后的剩余时长。
可选的，所述发送单元2202具体用于：
在所述非授权信道上发送第一信道预约信号，并在预设时间段之后，发送第二信道预约信号；所述第二信道预约信号所在的子帧上传输的数据的调制阶数小于或等于所述第一信道预约信号所预约的子帧上传输的数据的调制阶数，所述第二信道预约信号所在的子帧上传输的数据的编码率小于或等于所述第一信道预约信号所预约的子帧上传输的数据的编码率。
可选的，如图23所示，所述基站22还可以包括：转换单元2203，用于在发送单元2202在所述非授权信道上发送信道预约信号之前，对信道预约信号进行采样率转换，得到目标信号；其中，所述目标信号的采样率是LAA信号的采样率；该情况下，发送单元2202具体用于：在所述非授权信道上发送所述目标信号。
可选的，系统信号是WiFi信号；发送单元2202还用于：向目标终端发送请求发送RTS帧，其中，所述RTS帧的接收媒体访问控制MAC地址字段用于标记所述目标终端的WiFi芯片的MAC地址；以使得所述终端广播清除发送CTS帧，其中，所述CTS帧中标记用于表示待预约时长的信息，进而以使得接收到所述CTS帧的设备在所述待预约时长内不发送数据。
可选的，系统信号是WiFi信号；待预约时长为T；WiFi信号前导码和signal字段的组合所预约的最大时长是a，WiFi控制帧所预约的最大时长是b。该情况下，发送单元2201在非授权信道上发送信道预约信号，可以包括但不限于以下几种情况中的任一种：
当T≤a时，发送单元2201在该非授权信道上发送一组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或一组WiFi控制帧所表示的信道预约信号。
当a＜T≤b时，发送单元2201在该非授权信道上发送多组WiFi 信号前导码和signal字段的组合所表示的信道预约信号，或一组WiFi控制帧所表示的信道预约信号。
当T＞b时，发送单元2201在该非授权信道上发送多组WiFi信号前导码和signal字段的组合所表示的信道预约信号，或多组WiFi控制帧所表示的信道预约信号，或一组/多组WiFi信号前导码和signal字段的组合所表示的信道预约信号与一组/多组WiFi控制帧所表示的信道预约信号。
可选的，发送单元2201具体可以用于：在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On之前的1个或多个OFDM符号上发送信道预约信号；或者，在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On时，在Cell On开始的1个或多个OFDM符号上发送信道预约信号；或者，在Cell On/Off机制中，在非授权信道上，基站在其所属的LAA系统处于Cell On时，在Cell On开始的1个或多个数据区域的OFDM符号上发送信道预约信号。
可选的，若CCA检测的结果是非授权信道空闲，则发送单元2201具体用于：在非授权信道的用于承载控制数据的最后1个或多个OFDM符号上发送信道预约信号。
可选的，发送单元2201具体用于：若CCA的检测结果是非授权信道空闲，且T1≥T2，则在该CCA检测结束后延迟T1-T2时长，在非授权信道上发送信道预约信号，以预约非授权信道；或者，若CCA的检测结果是非授权信道空闲，且T1＜T2，则在非授权信道上发送信道预约信号，以预约非授权信道。其中，T1是基站所属的LAA系统的从上行传输切换到下行传输的时延，是所述基站将所述信道预约信号发送至空口所需要的时间。
可以理解，本发明实施例的基站22可对应于上述实施例所述的发送信道预约信号的方法中的基站，并且本发明实施例的基站22中 的各个模块的划分和/或功能等均是为了实现上述方法流程，为了简洁，在此不再赘述。
由于本发明实施例中的基站22可以用于执行上述方法流程，因此，其所能获得的技术效果也可参考上述方法实施例，本发明实施例在此不再赘述。
参见图24，为本发明实施例提供一种基站24的结构示意图。该基站24可以包括：处理器2401、存储器2402、系统总线2403和通信接口2404。
所述存储器2402用于存储计算机执行指令，所述处理器2401与所述存储器2402通过所述系统总线连接，当所述基站242运行时，所述处理器2401执行所述存储器2403存储的所述计算机执行指令，以使所述基站24执行上述任一种发送信道预约信号的方法。
具体的发送信道预约信号的方法可参见上文所示的实施例中的相关描述，此处不再赘述。
本实施例还提供一种存储介质，该存储介质可以包括所述存储器1202。
所述处理器2401可以为中央处理器(central processing unit，CPU)。所述处理器2401还可以为其他通用处理器、数字信号处理器(digital signal processing，DSP)、专用集成电路(application specific integrated circuit，ASIC)、现场可编程门阵列(field-programmable gate array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
所述处理器2401可以为专用处理器，该专用处理器可以包括基带处理芯片、射频处理芯片等中的至少一个。进一步地，该专用处理器还可以包括具有基站24其他专用处理功能的芯片。
所述存储器2402可以包括易失性存储器(volatile memory)，例 如随机存取存储器(random-access memory，RAM)；所述存储器2402也可以包括非易失性存储器(non-volatile memory)，例如只读存储器(read-only memory，ROM)，快闪存储器(flash memory)，硬盘(hard disk drive，HDD)或固态硬盘(solid-state drive，SSD)；所述存储器2402还可以包括上述种类的存储器的组合。
所述系统总线2403可以包括数据总线、电源总线、控制总线和信号状态总线等。本实施例中为了清楚说明，在图24中将各种总线都示意为系统总线2403。
所述通信接口2404具体可以是基站24上的收发器。该收发器可以为无线收发器。例如，无线收发器可以是基站24的天线等。所述处理器2401通过所述通信接口2404与其他设备，例如终端之间进行数据的收发。
在具体实现过程中，上述任一方法流程中的各步骤均可以通过硬件形式的处理器2401执行存储器2402中存储的软件形式的计算机执行指令实现。为避免重复，此处不再赘述。
由于本发明实施例提供的基站24可用于执行上述方法流程，因此其所能获得的技术效果可参考上述方法实施例，此处不再赘述。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的装置，仅以上述各功能模块的划分进行举例说明，实际应用中，可以根据需要而将上述功能分配由不同的功能模块完成，即将装置的内部结构划分成不同的功能模块，以完成以上描述的全部或者部分功能。上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统，装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述模块或单元的划分，仅仅为一种逻 辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本发明各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本发明的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)或处理器(processor)执行本发明各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、ROM、RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本发明的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应以所述权利要求的保护范围为准。

Claims (30)

  1. 一种发送信道预约信号的方法，其特征在于，包括：
    基站检测在非授权信道上是否接收到系统信号；
    若所述基站检测到在所述非授权信道上接收到所述系统信号，则所述基站在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
  2. 根据权利要求1所述的方法，其特征在于，若所述基站检测到在所述非授权信道上接收到所述系统信号，则所述基站在所述非授权信道上发送信道预约信号，以预约所述非授权信道，包括：
    若所述基站检测到在所述非授权信道上接收到所述系统信号，则所述基站进行空闲信道检测CCA；
    若所述CCA的检测结果是所述非授权信道空闲，则所述基站在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
  3. 根据权利要求2所述的方法，其特征在于，所述基站检测在所述非授权信道上是否接收到系统信号，包括：
    所述基站在每个检测周期内检测在所述非授权信道上是否接收到系统信号；其中，所述检测周期包括一个或多个检测时长；
    若所述基站检测到在所述非授权信道上接收到所述系统信号，则所述基站进行CCA，包括：
    若所述基站在任意一个所述检测时长内检测到在所述非授权信道上接收到所述系统信号，则所述基站停止在该检测时长所属的检测周期内检测所述系统信号，并进行CCA。
  4. 根据权利要求2或3所述的方法，其特征在于，所述基站进行CCA，包括：
    在小区打开或关闭Cell On/Off机制中，所述基站在所述基站所属的辅助授权接入LAA系统处于Cell On之前的N个子帧开始进行CCA；其中，所述N个子帧的时长大于或等于所述系统信号所属的系 统的一次数据发送的最大持续时长。
  5. 根据权利要求2-4任一项所述的方法，其特征在于，所述CCA满足以下至少一个条件：
    所述CCA的检测门限的取值范围小于或等于d；其中，所述d表示所述基站对同系统进行CCA时的检测门限以及对异系统进行CCA检测时的检测门限中的最小值；或者，
    所述CCA的检测时长大于或等于所述基站对同系统进行CCA时的检测时长以及对异系统进行CCA检测时的检测时长中的最大值；或者，
    所述CCA的时延defer时长大于或等于所述基站对同系统进行CCA时的defer时长以及对异系统进行CCA时的defer时长中的最大值。
  6. 根据权利要求2-5任一项所述的方法，其特征在于，所述基站在所述非授权信道上发送信道预约信号，包括：
    所述基站在所述非授权信道上连续发送S个信道预约信号；其中，第s个信道预约信号的预约字段用于标记所述第s+1个所述信道预约信号至所述第S个所述信道预约信号所占用的时长与待预约时长之和；其中，1≤s≤S，S和s均是整数，所述待预约时长是指在所述非授权信道上传输数据所需使用的时长。
  7. 根据权利要求2-5任一项所述的方法，其特征在于，所述基站在所述非授权信道上发送信道预约信号，包括：
    所述基站在所述非授权信道上的每个目标正交频分复用技术OFDM符号上发送信道预约信号；其中，所述目标OFDM符号是指从目标时刻所在的OFDM符号后的首个OFDM符号开始的P个OFDM符号，所述目标时刻是指所述基站确定所述CCA的检测结果是所述非授权信道空闲的时刻，所述P是大于或等于1的整数。
  8. 根据权利要求7所述的方法，其特征在于，若所述P大于1；
    第p个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记所述第p个所述目标OFDM符号上被所述信道预约信号占用后的剩余时长；第P个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记所述第P个所述目标OFDM符号上被所述信道预约信号占用后的剩余时长与待预约时长之和；其中，1≤p＜P，p是整数；
    或者，每个所述目标OFDM符号上发送的每个所述信道预约信号的预约字段用于标记该目标OFDM符号上被所述信道预约信号占用后的剩余时长与待预约时长之和；
    或者，第m个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记(P-m)*OFDM符号时长与待预约时长之和；其中，1≤m≤P，m是整数。
  9. 根据权利要求8所述的方法，其特征在于，所述系统信号是无线保真WiFi信号；所述目标OFDM符号上被所述信道预约信号占用后的剩余时长中还发送填充信息，所述填充信息包括以下信息中的任一种：
    WiFi控制帧；或者，
    WiFi信号前导码和信号signal字段的组合；或者，
    WiFi信号前导码、信号signal字段和无效数据的组合。
  10. 根据权利要求9所述的方法，其特征在于，
    若所述目标OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal字段和无效数据的组合，且所述目标OFDM符号中的填充信息在所述OFDM符号中的信道预约信号之后发送，所述signal字段中的长度字段标记为0；
    或者，若所述目标OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal 字段和无效数据的组合，且所述目标OFDM符号中的填充信息在所述OFDM符号中的信道预约信号之前发送，所述signal字段中的长度字段标记为0，或该目标OFDM符号上被所述信号前导码和所述signal字段占用后的剩余时长。
  11. 根据权利要求1-5任一项所述的方法，其特征在于，所述基站在所述非授权信道上发送信道预约信号，包括：
    所述基站在所述非授权信道上发送第一信道预约信号，并在预设时间段之后，发送第二信道预约信号；其中，所述第二信道预约信号所在的子帧上传输的数据的调制阶数小于或等于所述第一信道预约信号所预约的子帧上传输的数据的调制阶数，所述第二信道预约信号所在的子帧上传输的数据的编码率小于或等于所述第一信道预约信号所预约的子帧上传输的数据的编码率。
  12. 根据权利要求1-11任一项所述的方法，其特征在于，在所述基站在所述非授权信道上发送信道预约信号之前，所述方法还包括：
    所述基站对信道预约信号进行采样率转换，得到目标信号；其中，所述目标信号的采样率是LAA信号的采样率；
    所述基站在所述非授权信道上发送信道预约信号，包括：
    所述基站在所述非授权信道上发送所述目标信号。
  13. 根据权利要求1-12任一项所述的方法，其特征在于，所述系统信号是无线保真WiFi信号；所述方法还包括：
    所述基站向目标终端发送请求发送RTS帧，其中，所述RTS帧的接收媒体访问控制MAC地址字段用于标记所述目标终端的WiFi芯片的MAC地址；以使得所述终端广播清除发送CTS帧，其中，所述CTS帧中标记用于表示待预约时长的信息，进而以使得接收到所述CTS帧的设备在所述待预约时长内不发送数据。
  14. 根据权利要求1所述的方法，其特征在于，所述基站在所述 非授权信道上发送信道预约信号，包括：
    在小区打开或关闭Cell On/Off机制中，在非授权信道上，基站在其所属的辅助授权接入LAA系统处于Cell On之前的1个或多个正交频分复用技术OFDM符号上发送信道预约信号；或者，
    在小区打开或关闭Cell On/Off机制中，在非授权信道上，基站在其所属的辅助授权接入LAA系统处于Cell On时，在Cell On开始的1个或多个正交频分复用技术OFDM符号上发送信道预约信号；或者，
    在小区打开或关闭Cell On/Off机制中，在非授权信道上，基站在其所属的辅助授权接入LAA系统处于Cell On时，在Cell On开始的1个或多个数据区域的正交频分复用技术OFDM符号上发送信道预约信号。
  15. 根据权利要求2-10任一项所述的方法，其特征在于，若所述CCA的检测结果是所述非授权信道空闲，则所述基站在所述非授权信道上发送信道预约信号，以预约所述非授权信道，包括：
    若所述CCA的检测结果是所述非授权信道空闲，且T1≥T2，则所述基站在所述CCA检测结束后延迟T1-T2时长，在所述非授权信道上发送信道预约信号，以预约所述非授权信道；或者，
    若所述CCA的检测结果是所述非授权信道空闲，且T1＜T2，则所述基站在所述非授权信道上发送信道预约信号，以预约所述非授权信道；
    其中，所述T1是所述基站所属的辅助授权接入LAA系统的从上行传输切换到下行传输的时延，所述T2是所述基站将所述信道预约信号发送至空口所需要的时间。
  16. 一种基站，其特征在于，包括：检测单元和发送单元；
    所述检测单元，用于检测在非授权信道上是否接收到系统信号；
    若所述检测单元检测到在所述非授权信道上接收到所述系统信 号，则发送单元用于在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
  17. 根据权利要求16所述的基站，其特征在于，
    所述检测单元还用于：若检测到在所述非授权信道上接收到所述系统信号，则进行空闲信道检测CCA；
    所述发送单元具体用于：若所述CCA的检测结果是所述非授权信道空闲，则在所述非授权信道上发送信道预约信号，以预约所述非授权信道。
  18. 根据权利要求17所述的基站，其特征在于，
    所述发送单元具体用于：在每个检测周期内检测在所述非授权信道上是否接收到系统信号；其中，所述检测周期包括一个或多个检测时长；
    所述检测单元具体用于：若在任意一个所述检测时长内检测到在所述非授权信道上接收到所述系统信号，则停止在该检测时长所属的检测周期内检测所述系统信号；并进行CCA。
  19. 根据权利要求17或18所述的基站，其特征在于，所述检测单元在执行进行CCA时，具体用于：在小区打开或关闭Cell On/Off机制中，在所述基站所属的辅助授权接入LAA系统处于Cell On之前的N个子帧开始进行CCA；其中，所述N个子帧的时长大于或等于所述系统信号所属的系统的一次数据发送的最大持续时长。
  20. 根据权利要求17-19任一项所述的基站，其特征在于，所述CCA满足以下至少一个条件：
    所述CCA的检测门限的取值范围小于或等于d；其中，所述d表示所述基站对同系统进行CCA时的检测门限和对异系统进行CCA时的检测门限的最小值；或者，
    所述CCA的检测时长大于或等于所述基站对同系统进行CCA时的检测时长和对异系统进行CCA时的检测时长的最大值；或者，
    所述CCA的时延defer时长大于或等于所述基站对同系统进行CCA时的defer时长以及对异系统进行CCA时的defer时长中的最大值。
  21. 根据权利要求17-20任一项所述的基站，其特征在于，
    所述发送单元具体用于：在所述非授权信道上连续发送S个信道预约信号；其中，第s个信道预约信号的预约字段用于标记所述第s+1个所述信道预约信号至所述第S个所述信道预约信号所占用的时长与待预约时长之和；其中，1≤s≤S，S和s均是整数，所述待预约时长是指在所述非授权信道上传输数据所需使用的时长。
  22. 根据权利要求17-20任一项所述的基站，其特征在于，
    所述发送单元具体用于：在所述非授权信道上的每个目标正交频分复用技术OFDM符号上发送信道预约信号；其中，所述目标OFDM符号是指从目标时刻所在的OFDM符号后的首个OFDM符号开始的P个OFDM符号，所述目标时刻是指所述检测单元确定所述CCA的检测结果是所述非授权信道空闲的时刻，所述P是大于或等于1的整数。
  23. 根据权利要求22所述的基站，其特征在于，所述P大于1；
    第p个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记所述第p个所述目标OFDM符号上被所述信道预约信号占用后的剩余时长；第P个所述目标OFDM符号上发送的所述信道预约信号的预约字段用于标记所述第P个所述目标OFDM符号上被所述信道预约信号占用后的剩余时长与待预约时长之和；其中，1≤p＜P，p是整数；
    或者，每个所述目标OFDM符号上发送的每个所述信道预约信号的预约字段用于标记该目标OFDM符号上被所述信道预约信号占用后的剩余时长与待预约时长之和；
    或者，第m个所述目标OFDM符号上发送的所述信道预约信号 的预约字段用于标记(P-m)*OFDM符号时长与待预约时长之和；其中，1≤m≤P，m是整数。
  24. 根据权利要求23所述的基站，其特征在于，所述系统信号是无线保真WiFi信号；
    所述发送单元还用于：所述目标OFDM符号上被所述信道预约信号占用后的剩余时长中发送填充信息，所述填充信息包括以下信息中的任一种：
    WiFi控制帧；或者，
    WiFi信号前导码和信号signal字段的组合；或者，
    WiFi信号前导码、信号signal字段和无效数据的组合。
  25. 根据权利要求24所述的基站，其特征在于，
    若所述目标OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal字段和无效数据的组合，且所述目标OFDM符号中的填充信息在所述OFDM符号中的信道预约信号之后发送，所述signal字段中的长度字段标记为0；
    或者，若所述目标OFDM符号中的填充信息包括以下任一种：WiFi信号前导码和signal字段的组合，或者，WiFi信号前导码、signal字段和无效数据的组合，且所述目标OFDM符号中的填充信息在所述OFDM符号中的信道预约信号之前发送，所述signal字段中的长度字段标记为0，或该目标OFDM符号上被所述信号前导码和所述signal字段占用后的剩余时长。
  26. 根据权利要求16-20任一项所述的基站，其特征在于，
    所述发送单元具体用于：在所述非授权信道上发送第一信道预约信号，并在预设时间段之后，发送第二信道预约信号；其中，所述第二信道预约信号所在的子帧上传输的数据的调制阶数小于或等于所述第一信道预约信号所预约的子帧上传输的数据的调制阶数，所述第 二信道预约信号所在的子帧上传输的数据的编码率小于或等于所述第一信道预约信号所预约的子帧上传输的数据的编码率。
  27. 根据权利要求16-26任一项所述的基站，其特征在于，所述基站还包括：
    转换单元，用于在所述发送单元在所述非授权信道上发送信道预约信号之前，对信道预约信号进行采样率转换，得到目标信号；其中，所述目标信号的采样率是LAA信号的采样率；
    所述发送单元具体用于：在所述非授权信道上发送所述目标信号。
  28. 根据权利要求16-27任一项所述的基站，其特征在于，所述系统信号是无线保真WiFi信号；
    所述发送单元还用于：向目标终端发送请求发送RTS帧，其中，所述RTS帧的接收媒体访问控制MAC地址字段用于标记所述目标终端的WiFi芯片的MAC地址；以使得所述终端广播清除发送CTS帧，其中，所述CTS帧中标记用于表示待预约时长的信息，进而以使得接收到所述CTS帧的设备在所述待预约时长内不发送数据。
  29. 根据权利要求16所述的基站，其特征在于，所述基站发送单元具体用于：
    在小区打开或关闭Cell On/Off机制中，在非授权信道上，基站在其所属的辅助授权接入LAA系统处于Cell On之前的1个或多个正交频分复用技术OFDM符号上发送信道预约信号；或者，
    在小区打开或关闭Cell On/Off机制中，在非授权信道上，基站在其所属的辅助授权接入LAA系统处于Cell On时，在Cell On开始的1个或多个正交频分复用技术OFDM符号上发送信道预约信号；或者，
    小区打开或关闭Cell On/Off机制中，在非授权信道上，基站在其所属的辅助授权接入LAA系统处于Cell On时，在Cell On开始的 1个或多个数据区域的正交频分复用技术OFDM符号上发送信道预约信号。
  30. 根据权利要求17-25任一项所述的基站，其特征在于，所述发送单元具体用于：
    若所述CCA的检测结果是所述非授权信道空闲，且T1≥T2，则在所述CCA检测结束后延迟T1-T2时长，在所述非授权信道上发送信道预约信号，以预约所述非授权信道；或者，
    若所述CCA的检测结果是所述非授权信道空闲，且T1＜T2，则在所述非授权信道上发送信道预约信号，以预约所述非授权信道；
    其中，所述T1是所述基站所属的辅助授权接入LAA系统的从上行传输切换到下行传输的时延，所述T2是所述基站将所述信道预约信号发送至空口所需要的时间。
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