CN111699747A - Random access method and device thereof - Google Patents

Abstract

The embodiment of the application provides a random access method and a device thereof, wherein the method comprises the following steps: the method comprises the steps that a first communication device sends a random access preamble to a second communication device through a first uplink sub-band in M uplink sub-bands of a multi-sub-band system; the first communication device receives a random access response message from the second communication device through a second downlink sub-band in N downlink sub-bands of the multi-sub-band system, wherein M and N are positive integers, and M >1 or N > 1; the first communication device sends a third message to the second communication device through a third uplink sub-band in the M uplink sub-bands, wherein the third message comprises identification information of the first communication device; the first communication device receives a contention resolution message from the second communication device through a fourth downlink subband of the N downlink subbands. By adopting the embodiment of the application, the time consumed by the random access process can be shortened, and the efficiency of the random access process can be further improved.

Description

Random access method and device thereof Technical Field

The embodiment of the application relates to the technical field of communication, in particular to a random access method and a device thereof.

Background

A terminal device (e.g., a User Equipment (UE)) acquires downlink synchronization with a cell through a cell search procedure to receive downlink data. The terminal equipment establishes connection with the cell through a random access process and obtains uplink synchronization so as to perform uplink transmission.

The random access procedure may include the steps of: a, a base station broadcasts random access configuration information, including time frequency resources occupied by a random access channel, used random access lead codes and the like. And b, the terminal equipment receives the configuration parameter, and selects and sends the random access preamble when the initial random access process needs to be executed. And c, the base station detects possible random access lead codes, and sends a random access response message after the base station detects one or more random access lead codes. d, then the terminal device tries to receive the random access response message sent to it by the base station in the pre-configured random access response message receiving window, if the terminal device fails to receive the random access response message sent to it by the base station, the terminal device re-initiates the random access process; if the terminal equipment receives the random access response message sent to the terminal equipment by the base station, the terminal equipment sends a message III on the allocated uplink resource, wherein the message III comprises the identification information of the terminal equipment. And e, after receiving the message III of the terminal equipment, the base station sends a competition resolving message to the terminal equipment, wherein the competition resolving message comprises the identification information of the terminal equipment. After receiving the contention resolution message, the terminal device determines whether the random access process is successful by detecting whether the identification information carried by the contention resolution message is the same as the identification information carried by the message three.

In a communication system, under the condition that a channel required to be used by each message in the random access process is occupied or interfered by a higher priority service or other systems, the sending opportunity of each message is reduced, and further the random access process consumes longer time.

Disclosure of Invention

The technical problem to be solved in the embodiments of the present application is to provide a random access method and a device thereof, which can shorten the time consumed by a random access process, and further can improve the efficiency of the random access process.

A first aspect of an embodiment of the present application provides a random access method, including:

the method comprises the steps that a first communication device sends a random access preamble to a second communication device through a first uplink sub-band in M uplink sub-bands of a multi-sub-band system;

the first communication device receives a random access response message from the second communication device through a second downlink sub-band in N downlink sub-bands of the multi-sub-band system, wherein M and N are positive integers, and M >1 or N > 1;

the first communication device sends a third message to the second communication device through a third uplink sub-band in the M uplink sub-bands, wherein the third message comprises identification information of the first communication device;

the first communication device receives a contention resolution message from the second communication device through a fourth downlink sub-band of the N downlink sub-bands;

the downlink sub-band corresponding to the first uplink sub-band is a first downlink sub-band, the uplink sub-band corresponding to the second downlink sub-band is a second uplink sub-band, the downlink sub-band corresponding to the third uplink sub-band is a third downlink sub-band, and the uplink sub-band corresponding to the fourth downlink sub-band is a fourth uplink sub-band;

the first uplink sub-band, the third uplink sub-band, the first downlink sub-band, the second downlink sub-band and the fourth downlink sub-band at least satisfy one of the following conditions:

the third uplink sub-band is different from the first uplink sub-band; or the like, or, alternatively,

at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band.

A second aspect of embodiments of the present application provides a first communication device, which includes means for performing the steps of the first aspect.

A third aspect of an embodiment of the present application provides a first communications apparatus, including at least one processing element and at least one memory element, where the at least one memory element is configured to store a program and data, and the at least one processing element is configured to execute the method provided in the first aspect of the embodiment of the present application.

A fourth aspect of embodiments of the present application provides a first communications device, comprising at least one processing element (or chip) configured to perform the method of the first aspect above.

A fifth aspect of embodiments of the present application provides a program, which when executed by a processor is configured to perform the method of the first aspect.

A sixth aspect of embodiments herein provides a program product, e.g., a computer readable storage medium, embodying the program of the fifth aspect.

It can be seen that, in the first to sixth aspects, by arranging each uplink message and each downlink message in the random access process on a plurality of subbands, the time consumed in the random access process can be shortened, and the efficiency of the random access process can be further improved.

The method provided by the first aspect is applied to a multi-sub-band system of the unlicensed spectrum, the success rate of listening before speaking on a plurality of sub-bands is greater than the success rate of listening before speaking on a single sub-band, and therefore time consumed in the random access process can be shortened, and efficiency of the random access process can be improved.

The method provided by the first aspect is applied to a multi-subband system of a licensed spectrum, and the efficiency of a random access process can be improved under the condition that a plurality of first communication devices use the same time-frequency resource to transmit the same random access preamble.

With reference to the first to sixth aspects, in a possible implementation manner, before the first communication device transmits the random access preamble to the second communication device through the first uplink subband in the M uplink subbands of the multi-subband system, the random access configuration information is received from the second communication device, where the random access configuration information is used to indicate M1 uplink subbands in the M uplink subbands and N1 downlink subbands in the N downlink subbands. The M1 uplink subbands include a first uplink subband used for transmitting a random access preamble, and the N1 downlink subbands include a second downlink subband used for transmitting a random access response message and a fourth downlink subband used for transmitting a contention resolution message. And the random access configuration is more flexible through the indication of the random access configuration information.

With reference to the first to sixth aspects, in a possible implementation manner, the M1 uplink subbands are candidate uplink subbands for the first communication device to send the random access preamble to the second communication device, where the candidate uplink subbands refer to a set of uplink subbands selectable by the first communication device to send the random access preamble, and the set of uplink subbands is available for the second communication device to detect and receive the random access preamble and the message three. The first communication device may select one uplink subband from the candidate uplink subbands to transmit the random access preamble, and the second communication device may detect and receive the random access preamble and the message three on all the candidate uplink subbands.

The N1 downlink subbands are candidate downlink subbands used for the second communications apparatus to send a random access response message and a contention resolution message to the first communications apparatus, where the candidate downlink subbands refer to a set of downlink subbands selectable for the second communications apparatus to send the random access response message and the contention resolution message, and the set of downlink subbands may be used for the first communications apparatus to detect and receive the random access response message and the contention resolution message. That is, the second communication apparatus may select one downlink sub-band from the candidate downlink sub-bands to transmit the random access response message, select one downlink sub-band from the candidate downlink sub-bands to transmit the contention resolution message, and the first communication apparatus may detect and receive the random access response message and the contention resolution message on all the candidate downlink sub-bands.

With reference to the first to sixth aspects, in a possible implementation manner, the random access response message is used to indicate uplink resource allocation information of K1 uplink subbands among the M uplink subbands, that is, to indicate which uplink subbands are available for sending the message three. The first communication device may select a third uplink sub-band from the K1 uplink sub-bands and transmit message three using the third uplink sub-band.

The second communication device can schedule the first communication device through the random access response message according to the proportion of idle and busy detected by the channels on each downlink sub-band, and can send a message three on the K1 uplink sub-band, and under the condition that the M value is larger, the processing complexity of the second communication device can be reduced.

With reference to the first to sixth aspects, in a possible implementation manner, in a case that the second communication apparatus does not receive the message three, the first communication apparatus receives a message three retransmission scheduling message from the second communication apparatus, where the message three retransmission scheduling message is used to indicate uplink resource allocation information of K2 uplink subbands among the M uplink subbands; the first communication device retransmits the message three to the second communication device via one of the K2 upstream subbands. The second communication device may schedule K2 uplink subbands from the M uplink subbands to retransmit the message three to the first communication device by retransmitting the scheduling message with the message three, so as to improve the probability that the second communication device successfully receives the message three.

With reference to the first to sixth aspects, in a possible implementation manner, K1 is not greater than K2, and the second communication device may increase the number of uplink sub-bands for scheduling message three transmission to improve the success rate of listening first and then speaking on the multiple uplink sub-bands, thereby improving the probability of success of message three retransmission.

With reference to the first to sixth aspects, in one possible implementation manner, the first communication device listens before speak for M or M1 uplink sub-bands, selects one uplink sub-band from the uplink sub-bands that successfully listen before speak with the same probability, and determines the selected uplink sub-band as the first uplink sub-band, which is simple to implement. Likewise, the first communication device may determine the third upstream sub-band from the K1 upstream sub-bands in this manner.

With reference to the first to sixth aspects, in a possible implementation manner, the first communication device listens before talk to M or M1 uplink subbands, selects an uplink subband with a minimum energy detection value from the uplink subbands that successfully listen before talk, and determines the uplink subband as the first uplink subband, so that the random access preamble is less interfered when transmitted on the first uplink subband. Likewise, the first communication device may determine the third upstream sub-band from the K1 upstream sub-bands in this manner.

A seventh aspect of the present embodiment provides a random access method, including:

the second communication device receives a random access preamble from the first communication device through a first uplink subband among M uplink subbands of the multi-subband system;

the second communication device sends a random access response message to the first communication device through a second downlink sub-band in N downlink sub-bands of the multi-sub-band system, wherein M and N are positive integers, and M >1 or N > 1;

the second communication device receives a third message from the first communication device through a third uplink sub-band of the M uplink sub-bands, wherein the third message comprises identification information of the first communication device;

the second communication device sends a competition resolving message to the first communication device through a fourth downlink sub-band in the N downlink sub-bands;

the downlink sub-band corresponding to the first uplink sub-band is a first downlink sub-band, the uplink sub-band corresponding to the second downlink sub-band is a second uplink sub-band, the downlink sub-band corresponding to the third uplink sub-band is a third downlink sub-band, and the uplink sub-band corresponding to the fourth downlink sub-band is a fourth uplink sub-band;

the first uplink sub-band, the third uplink sub-band, the first downlink sub-band, the second downlink sub-band and the fourth downlink sub-band at least satisfy one of the following conditions:

the third uplink sub-band is different from the first uplink sub-band; or the like, or, alternatively,

at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band.

An eighth aspect of the embodiments of the present application provides a second communication device, which includes means or units (means) for performing the steps of the seventh aspect.

A ninth aspect of this embodiment of the present application provides a second communication apparatus, including at least one processing element and at least one memory element, where the at least one memory element is configured to store a program and data, and the at least one processing element is configured to execute the method provided in the seventh aspect of this embodiment of the present application.

A tenth aspect of embodiments of the present application provides a second communication device, including at least one processing element (or chip) for performing the method of the above seventh aspect.

An eleventh aspect of embodiments of the present application provides a program, which when executed by a processor, is configured to perform the method of the seventh aspect.

A twelfth aspect of embodiments of the present application provides a program product, such as a computer-readable storage medium, including the program of the eleventh aspect.

It can be seen that, in the seventh to twelfth aspects, by arranging each uplink message and each downlink message in the random access process on a plurality of subbands, the time consumed in the random access process can be shortened, and the efficiency of the random access process can be further improved.

The method provided by the seventh aspect is applied to a multi-sub-band system of the unlicensed spectrum, and the success rate of listening before speaking on a plurality of sub-bands is greater than the success rate of listening before speaking on a single sub-band, so that the time consumed in the random access process can be shortened, and the efficiency of the random access process can be improved.

Applying the method provided in the seventh aspect to a multi-subband system of a licensed spectrum, the efficiency of the random access procedure may be improved when multiple first communication devices use the same time-frequency resource to transmit the same random access preamble.

With reference to the seventh to twelfth aspects, in a possible implementation manner, before the second communication device receives the random access preamble from the first communication device through the first uplink subband of the M uplink subbands of the multi-subband system, the second communication device transmits the random access configuration information to the first communication device. The description of the random access configuration information may refer to the description in the first aspect, and is not repeated herein.

With reference to the seventh to twelfth aspects, in a possible implementation manner, if the second communication device does not receive the third message from the first communication device, that is, the second communication device does not successfully decode the third message, a third message retransmission scheduling message is sent to the first communication device, where the third message retransmission scheduling message is used to indicate uplink resource allocation information of K2 uplink subbands among the M uplink subbands, that is, the first communication device allocates K2 uplink subbands for resending the third message. The second communication device receives a retransmission of message three from the first communication device through one of the K2 uplink subbands, that is, receives message three retransmitted by the first communication device. The second communication device retransmits the scheduled message via message three in order to increase the probability of successfully receiving message three.

With reference to the seventh to twelfth aspects, in a possible implementation manner, K1 is not greater than K2, and the second communication device may increase the number of uplink sub-bands for scheduling message three transmission to improve the success rate of listening before speaking on the multiple uplink sub-bands, so as to improve the probability of success of message three retransmission.

With reference to the seventh to twelfth aspects, in one possible implementation manner, the second communications device performs listen before talk on N or N1 downlink subbands, selects one downlink subband from the downlink subbands that have been successfully listened before talk with the same probability, and determines the selected downlink subband as the second downlink subband, which is simple to implement. Similarly, the second communications device may determine the fourth downlink subband from the N downlink subbands in this manner.

With reference to the seventh to twelfth aspects, in a possible implementation manner, the second communications device listens first and then speaks to N or N1 downlink sub-bands, selects a downlink sub-band with the smallest energy detection value from the downlink sub-bands that successfully listen first and then speak, and determines the downlink sub-band as the second downlink sub-band, so that the random access response message is less interfered when transmitted on the second downlink sub-band. Similarly, the second communications device may determine the fourth downlink subband from the N downlink subbands in this manner.

With reference to the seventh to twelfth aspects, in a possible implementation manner, in a case that at least two first communication apparatuses use the same time-frequency resource to transmit the same random access preamble to a second communication apparatus, and the second communication apparatus receives at least two messages three, the second communication apparatus transmits a contention resolution message to each first communication apparatus, where the contention resolution message includes at least two pieces of identification information, and any two pieces of identification information are different. For example, when two first communication devices use the same time-frequency resource to transmit the same random access preamble to the second communication device, and the second communication device receives the two messages three, the contention resolution message transmitted by the second communication device to the first communication device includes two different pieces of identification information. In this case, the message three sent by the first communication device occupies different sub-bands, and different first communication devices are distinguished, so as to improve the efficiency of the random access process.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present application, the drawings required to be used in the embodiments or the background art of the present application will be described below.

FIG. 1 is a schematic diagram of a listen-before-talk principle;

fig. 2 is a schematic view of carrier aggregation;

fig. 3 is a schematic diagram of a contention-based random access procedure;

fig. 4 is a flowchart illustrating a random access method according to an embodiment of the present application;

FIG. 5a is a schematic diagram of the embodiment shown in FIG. 4 applied in a time division duplex scenario;

FIG. 5b is a diagram illustrating the embodiment shown in FIG. 4 applied in a frequency division duplex scenario;

fig. 6 is a schematic logical structure diagram of a first communication device according to an embodiment of the present application;

fig. 7 is a simplified block diagram of a first communication device according to an embodiment of the present disclosure;

fig. 8 is a schematic logical structure diagram of a second communication apparatus according to an embodiment of the present application;

fig. 9 is a simplified schematic physical structure diagram of a second communication device according to an embodiment of the present disclosure.

Detailed Description

Reference will now be made to the following terms or terms referring to the embodiments of the present application:

(1) listen Before Talk (LBT) refers to a device that needs to transmit data needs to detect the wireless environment of a wireless carrier before sending data on the wireless carrier to determine whether other devices are transmitting data. When detecting that the energy on the wireless carrier is greater than a threshold, considering that other devices are transmitting data, and trying to send data after the devices avoid for a period of time; when it is detected that the energy on the wireless carrier is less than the threshold, the wireless carrier is considered to be in an idle state, and the device transmits data on the wireless carrier, which can be seen from the schematic diagram of the principle of listening before speaking shown in fig. 1.

If a device needing data transmission detects that the energy on a certain wireless carrier is less than a threshold, the device can be considered to have successful LBT on the wireless carrier; conversely, the apparatus may be deemed to have failed LBT on the wireless carrier if the apparatus detects that the energy on the wireless carrier is greater than a threshold.

LBT is applied in unlicensed spectrum scenarios, and LBT may not be performed in response to licensed spectrum scenarios.

(2) The first communication device may be a terminal device or a processing chip/element of the terminal device. The terminal device may be a UE, a Mobile Station (MS), a Mobile Terminal (MT), or the like, and is a device that provides voice and/or data connectivity to a user, for example, a handheld device with a wireless connection function, a vehicle-mounted device, or the like. Currently, some examples of terminals are: a mobile phone (mobile phone), a tablet computer, a notebook computer, a palm top computer, a Mobile Internet Device (MID), a wearable device, a Virtual Reality (VR) device, an Augmented Reality (AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in unmanned driving (self), a wireless terminal in remote operation (remote medical supply), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (smart), a wireless terminal in city (smart city), a wireless terminal in home (smart home), and the like.

(3) The second communication device may be an access network device or a processing chip/element of the access network device. The access network is a part of the network that accesses the terminal device to the wireless network. The access network device is a device in the radio access network, which may also be referred to as a base station. Currently, some examples of access network devices are: a base station, a Transmission Reception Point (TRP), an evolved Node B (eNB), a Radio Network Controller (RNC), a Node B (NB), a Base Station Controller (BSC), a Base Transceiver Station (BTS), a home base station (e.g., home evolved Node B, or home Node B, HNB), a Base Band Unit (BBU), or a wireless fidelity (Wifi) access point (access point, AP) in the 5G system.

The message sent by the base station to the UE is called a downlink message, and the message sent by the UE to the base station is called an uplink message. In this embodiment, a message sent by the first communication device to the second communication device is an uplink message, and a message sent by the second communication device to the first communication device is a downlink message.

(4) A multi-subband system refers to a communication device (e.g., UE, base station, etc.) whose operating bandwidth is divided into a plurality of continuous subbands or a plurality of discontinuous subbands, and the communication device can use one or more subbands to communicate with a corresponding communication device, for example, the UE can use one or more subbands to communicate with the base station. The random access method provided by the embodiment of the application can be applied to a multi-subband system.

The multi-subband system may be a Carrier Aggregation (CA) system, and the subbands are Component Carriers (CCs). The multi-subband system may also be a fifth generation mobile communication (5)^thGeneration, 5G) multiple bandwidth parts (BWP) in one cell in a New Radio (NR) system, where the sub-band is BWP.

In the embodiment of the present application, a cell which is composed of one uplink subband and one downlink subband and can provide communication service for a terminal device in a multi-subband system is referred to as a subband pair. If the downlink sub-band forming the sub-band pair with the uplink sub-band 1 is sub-band 1, the downlink sub-band corresponding to the uplink sub-band 1 can be called as downlink sub-band 1; if the uplink subband forming a subband pair with the downlink subband 2 is the uplink subband 2, the uplink subband corresponding to the downlink subband 2 may be referred to as the uplink subband 2. The subband pair may be a CC pair or a BWP pair.

Taking CC as an example, a CC pair is composed of an uplink CC and a downlink CC, and the CC pair is a cell capable of providing communication service for the terminal device. If the downlink CC forming the CC pair with the uplink CC1 is the downlink CC1, the downlink CC corresponding to the uplink CC1 may be referred to as the downlink CC 1; if the uplink CC forming the CC pair with the downlink CC2 is the uplink CC2, the uplink CC corresponding to the downlink CC2 may be referred to as the uplink CC 2.

The carrier aggregation technology can aggregate a plurality of CCs together, thereby realizing a transmission bandwidth larger than that of a single unit carrier, and effectively improving the uplink and downlink transmission rate. See the carrier aggregation diagram shown in fig. 2.

Each of the 4 CCs shown in fig. 2 may be used for uplink or downlink transmission in a Time Division Duplex (TDD) manner. The 4 CCs shown in fig. 2 may also be used for uplink or downlink transmission in a Frequency Division Duplex (FDD) manner, for example, the CCs 1 and 2 are used for uplink transmission, and the CCs 3 and 4 are used for downlink transmission.

Currently, in a carrier aggregation scenario of a Long Term Evolution (LTE) system, only one CC (applied to a TDD scenario) or one CC pair (applied to an FDD scenario) in a plurality of CCs is used as a main CC or a main CC pair of a UE, and the UE can only initiate random access on the main CC or the main CC pair.

For example, when the 4 CCs shown in fig. 2 adopt the TDD mode for uplink and downlink transmission, and one CC (for example, CC1) is used as the main CC of the UE, the UE can only send each uplink message of random access on CC1, and the base station can only send each downlink message of random access to the UE on CC 1.

For another example, when the 4 CCs shown in fig. 2 adopt the FDD mode for uplink and downlink transmission, assuming that CC1 and CC2 are used for uplink transmission, CC3 and CC4 are used for downlink transmission, and the base station configures a CC pair (e.g., { CC1, CC3}) for the UE as a primary CC pair of the UE, then the UE can only send each uplink message of random access on CC1, and the base station can only send each downlink message of random access to the UE on CC 3.

At present, the carrier aggregation scenario of the NR system is similar to that of the LTE system, and the UE can only initiate random access on the primary CC or the primary CC pair. The carrier aggregation scenario of the NR system is different from that of the LTE system in that, in NR, two primary CC pairs may be allocated to a UE according to the channel condition of the UE in a cell: under the condition of better uplink channel quality (low path loss), allocating a main CC pair { CC01, CC 01' } for the UE; in case of poor uplink channel quality (high path loss), the UE is assigned another primary CC pair { CC01, CC02 }. Two primary CC pairs are one of the main characteristics of a supplementary uplink carrier (SUL) in the NR system.

Wherein, CC01 is a downlink CC, CC01 ' and CC02 are uplink CCs, CC01 and CC01 ' may be the same CC in a TDD scenario, and CC01 and CC01 ' are different CCs in an FDD scenario. The reason why two main CC pairs are allocated to the UE according to the channel quality of the UE is that the path loss of a signal in a high frequency band (for example, 3.5GHz band) is greater than the path loss of a signal in a low frequency band (for example, 1.8GHz band), the maximum transmission power that can be supported by the base station is higher, which can make up for the larger path loss in the high frequency band in the random access process, and the transmission power that can be supported by the UE is lower, which cannot make up for the larger path loss in the high frequency band in the random access process, so that in the case of bad uplink channel quality (high path loss), the second main CC pair is selected for initial random access, thereby reducing the influence of the path loss on the initial random access.

The SUL scenario, i.e., the scenario in which two primary CC pairs ({ CC01, CC 01' } and { CC01, CC02}) are configured, is applicable to a TDD scenario and an FDD scenario. In the FDD scenario, CC01 is at a different frequency than CC 01', and CC01 is at a different frequency than CC 02. In the TDD scenario, CC01 is the same frequency as CC 01', and CC01 is a different frequency than CC 02; alternatively, CC01 and CC 01' are at different frequencies, and CC01 and CC02 are at the same frequency.

For convenience of description, in the embodiment of the present application, two uplink CCs in the SUL scene, namely, the CC 01' and the CC02, may be referred to as a high-frequency uplink CC and an auxiliary uplink CC, respectively.

(5) Unlicensed spectrum, which may also be referred to as unlicensed spectrum, refers to spectrum that may be used by any terminal device. The authorized spectrum refers to a spectrum owned by an authorized terminal device.

(6) The first uplink sub-band is an uplink sub-band occupied by the random access preamble sent by the first communication device to the second communication device. And the downlink sub-band corresponding to the first uplink sub-band is the first downlink sub-band.

And the second downlink sub-band is a downlink sub-band occupied by the second communication device for sending the random access response message to the first communication device. And the uplink sub-band corresponding to the second downlink sub-band is the second uplink sub-band.

And the third uplink sub-band is the uplink sub-band occupied by the first communication device for sending the message three to the second communication device. And the downlink sub-band corresponding to the third uplink sub-band is the third downlink sub-band.

And the fourth downlink sub-band is a downlink sub-band occupied by the second communication device for sending the contention resolution message to the first communication device. And the uplink sub-band corresponding to the fourth downlink sub-band is the fourth uplink sub-band.

The random access method provided by the embodiment of the application is a contention-based random access method, and a contention-based random access process is described in detail below. Please refer to fig. 3, which is a diagram illustrating a contention-based random access procedure.

1. And the base station sends the random access configuration information to the UE. Accordingly, the UE receives random access configuration information from the base station.

And the base station broadcasts the random access configuration information to the UE in the cell. The random access configuration information includes time-frequency resources occupied by a random access channel, a used random access preamble, a backoff value (the backoff indicator) when the random access procedure fails, and the like. The time-frequency resource occupied by the access channel may be parameters such as an initial position, a subframe number, and a period of a Physical Random Access Channel (PRACH).

The backoff value is used for indicating the first communication device which fails in random access, and random access is re-initiated after the time indicated by the backoff value, so that the collision problem caused by excessive number of terminal devices which initiate the contention-based random access is reduced.

2. The UE transmits a random access preamble to the base station. Accordingly, the UE receives the random access preamble from the base station.

And the UE selects time-frequency resources and sends a random access lead code under the condition of receiving the random access configuration information broadcasted by the base station and the condition of needing to initiate a random access process. The random access preamble may also be referred to as message one.

3. And the base station sends a random access response message to the UE. Accordingly, the UE receives a random access response message from the base station.

And the base station detects the random access lead code on the time-frequency resource of the random access lead code sent by the UE. When the base station detects one or more random access preambles, it sends a random access response message, where the random access response message carries Uplink (UL) resources allocated to the UE and also carries a new backoff value, and the UE updates the backoff value when receiving the random access response message. The random access response message may also be referred to as message two.

Wherein the random access response message may be in response to multiple random access preamble codes, which may use the same time-frequency location, but the content of the multiple random access preamble code transmissions (i.e., preamble codes) may be different. In other words, the random access response message is used to respond to a group of random access preambles that are identical in time-frequency location but different in preamble usage.

The format of the random access response message includes a field indicating a backoff value, a field indicating a random access preamble identifier, a field indicating uplink resource allocation information, a field indicating a Timing Advance (TA), and a field indicating a temporary cell-radio network temporary identity (TC-RNTI).

4. And the UE sends a message III to the base station. Accordingly, the base station receives message three from the UE.

After the UE sends the random access preamble, a random access-radio network temporary identity (RA-RNTI) is determined according to a time-frequency resource used for sending the random access preamble. And the UE monitors the random access response message sent by the second communication device within a configured monitoring window time by using the RA-RNTI after a certain time.

And if the UE does not receive the random access response message sent by the base station, the UE reinitiates the random access process and selects the opportunity for reinitiating the random access process according to the indication of the backoff value. The opportunity may refer to sending fixed time-frequency resources of the random access preamble, i.e. the random access preamble can only be sent on these fixed time-frequency resources, and the location of these time-frequency resources may be broadcasted by the random access configuration information. The timing may also refer to sending a fixed symbol on a fixed time slot of the random access preamble, that is, the random access preamble can only be sent on the fixed symbol on the fixed time slot, and the fixed symbol on the fixed time slot may be broadcasted by the random access configuration information.

And if the UE receives the random access response message sent by the base station, the UE sends a third message by using the uplink resource in the random access response message distribution, wherein the third message carries the identification information of the UE.

After the UE sends the message three according to the allocated uplink resource, the UE tries to receive a contention resolution message or a message three retransmission scheduling message within the timer time. And the UE resends the message III to the base station and initializes the timer when receiving the message III retransmission scheduling message.

And after the UE sends the message III according to the allocated uplink resource, the base station detects whether the message III is received on the uplink resource allocated to the UE. And if the base station does not receive the message three on the resource, the base station sends a message three retransmission scheduling message to the UE.

And the identification information of the UE carried by the message III is used for conflict resolution.

For a Radio Resource Control (RRC) connected UE, the identity information of the UE is a cell-radio network temporary identity (C-RNTI).

For the UE in the RRC idle state, the identification information of the UE is a temporary mobile subscriber identity number (S-TMSI) or a random number. Wherein, the S-TMSI is the identification allocated to the UE by the core network. Under the condition that the UE allocates the S-TMSI, the message III carries the S-TMSI; in case the UE is not allocated S-TMSI, message three carries a random number.

5. The base station sends a contention resolution message to the UE. Accordingly, the UE receives a contention resolution message from the base station.

And the base station sends a competition resolving message to the terminal equipment under the condition of receiving the message III sent by the UE, namely under the condition that the base station successfully decodes to obtain the message III, wherein the competition resolving message carries the identification information of the UE. Under the condition that the UE receives the competition resolving message, the UE detects whether the identification information of the UE carried by the competition resolving message is the same as the identification information carried by the message III sent by the UE, and if so, the competition random access is successful; if not, the contention random access fails. The contention resolution message may also be referred to as message four.

And in the timer time, if the UE does not receive a competition resolving message carrying the identification information of the UE or does not receive a message three-retransmission scheduling message, the random access is considered to be failed, the UE re-initiates a random access process, and selects the timing of re-initiating the random access process according to the indication of the backoff value.

The contention-based random access procedure shown in fig. 3 is applied in a unlicensed spectrum communication system and may be affected by LBT. In a TDD scenario, a UE attempts to send a random access preamble on multiple CCs, sends the random access preamble after LBT succeeds on a certain CC, and then the base station sends a random access response message, a UE sends a message three, and the base station sends a contention resolution message all need to be performed on the CC. In an FDD scenario, a UE tries to send a random access preamble on a plurality of uplink CCs, sends the random access preamble after LBT on a certain uplink CC is successful, and then a base station sends a random access response message and a contention resolution message on a downlink CC corresponding to the uplink CC, and a UE sends a message three on the uplink CC. In other words, the message sent by the base station to the UE and the message sent by the UE to the base station need to use the same CC or the same CC pair, which results in a long time consumption for the random access procedure.

In view of the drawback of long time consumption in the current random access process, embodiments of the present application provide a random access method and apparatus, where each uplink message and each downlink message in the random access process are arranged on multiple subbands, the subbands for transmitting each message may be in a many-to-many relationship, and the success rate of LBT on multiple subbands is greater than the success rate of LBT on a single subband, thereby reducing the time consumed in the random access process and improving the efficiency of the random access process.

The random access method and the device thereof provided by the embodiment of the application can be applied to a multi-sub-band system of an unlicensed spectrum and can also be applied to a multi-sub-band system of a licensed spectrum.

The random access method provided by the embodiments of the present application will be described in detail below, and the random access method may be a contention-based random access method.

Referring to fig. 4, a flow chart of a random access method provided in the embodiment of the present application is schematically illustrated, where the method may include, but is not limited to, the following steps:

in step S401, the first communication device transmits a random access preamble to the second communication device through a first uplink subband of M uplink subbands of the multi-subband system. Accordingly, the second communication device receives the random access preamble from the first communication device through the first uplink sub-band.

In step S402, the second communication device sends a random access response message to the first communication device through a second downlink subband of the N downlink subbands of the multi-subband system. Accordingly, the first communication device receives a random access response message from the second communication device through the second downlink sub-band.

In step S403, the first communication device sends a third message to the second communication device through a third uplink subband in the M uplink subbands, where the third message includes identification information of the first communication device. Accordingly, the second communication device receives message three from the first communication device via the third uplink sub-band.

In step S404, the second communication device sends a contention resolution message to the first communication device through the fourth downlink subband of the N downlink subbands. Accordingly, the first communication device receives the contention resolution message from the second communication device through the fourth downlink sub-band.

Wherein M and N are positive integers, and M >1 or N > 1.

In one example, the first uplink sub-band is one of the M uplink sub-bands, the second downlink sub-band is one of the N downlink sub-bands, the third uplink sub-band is one of the M uplink sub-bands, and the fourth downlink sub-band is one of the N downlink sub-bands.

In one example, before step S401, the second communication device may send random access configuration information to the first communication device, where the random access configuration information includes time-frequency resources occupied by a random access channel, a used random access preamble, a backoff value when a random access procedure fails, and the like.

The second communication device may send the random access configuration information to the first communication device in a broadcast manner. The second communications device may perform LBT on the N downlink subbands and broadcast the random access configuration information on all downlink subbands for which LBT is successful.

In one example, the random access configuration information is further used to indicate M1 of the M uplink subbands and N1 of the N downlink subbands, M1 ≦ M, and N1 ≦ N. Wherein the M1 upstream sub-bands include a first upstream sub-band and the N1 downstream sub-bands include a second downstream sub-band and a fourth downstream sub-band.

The M1 uplink subbands are candidate uplink subbands for the first communication device to send the random access preamble to the second communication device, and the N1 downlink subbands are candidate downlink subbands for the second communication device to send the random access response message and the contention resolution message to the first communication device.

The candidate uplink sub-band refers to a set of uplink sub-bands selectable by the first communication device for sending the random access preamble, and the set of uplink sub-bands can be used by the second communication device for detecting and receiving the random access preamble and the message three. The candidate downlink sub-band refers to a set of downlink sub-bands selectable by the second communication device to send the random access response message and the contention resolution message, and the set of downlink sub-bands can be used by the first communication device to detect and receive the random access response message and the contention resolution message.

It is to be appreciated that one uplink sub-band of the M1 uplink sub-bands is used for the first communication device to transmit the random access preamble to the second communication device, and the second communication device can detect and receive the random access preamble and message three on the M1 uplink sub-bands. One downlink sub-band of the N1 downlink sub-bands is used for the second communication device to transmit a random access response message to the first communication device, one downlink sub-band of the N1 downlink sub-bands is used for the second communication device to transmit a contention resolution message to the first communication device, and the first communication device may detect and receive the random access response message and the contention resolution message on the N1 downlink sub-bands. In other words, the random access configuration information may be used to indicate that M1 uplink subbands among the M uplink subbands may be used for the first communication device to transmit the random access preamble to the second communication device, and the first communication device may select one uplink subband from the M1 uplink subbands to transmit the random access preamble; the indication unit may be configured to indicate that N1 downlink subbands from the N downlink subbands are available for the second communication device to send a random access response message and a contention resolution message to the first communication device, the second communication device may select one downlink subband from the N1 downlink subbands to send the random access response message, and may select one downlink subband from the N1 downlink subbands to send the contention resolution message.

And the M1 uplink sub-bands and the N1 downlink sub-bands are indicated through the random access configuration information, so that the random access configuration is more flexible. For example, where one of the uplink sub-bands transmits high priority traffic, the second communication device may configure the first communication device to transmit a random access preamble on the remaining 3 uplink sub-bands, i.e., M1 ═ 3; in the case where none of the 4 uplink sub-bands is transmitting high priority traffic, the second communication device may configure the first communication device to transmit the random access preamble on the 4 uplink sub-bands, i.e., M1 is 4.

In one example, a communication device may select a subband from a plurality of LBT successful subbands for transmitting a message by several selection means. The communication device may be a first communication device or a second communication device.

The selection mode is as follows: the communication device selects one subband with the same probability from the subbands for which LBT was successful. For example, if the number of LBT successful subbands is 3, the communication device selects one subband from the 3 LBT successful subbands with a probability of 1/3. As another example, if the number of LBT successful subbands is 1, the communication device selects 1/1 with a probability of successful LBT. It will be appreciated that each sub-band for which LBT succeeds is selected with the same probability. This way is simple to implement.

In the second selection method, the communication apparatus selects a subband having the smallest energy detection value from subbands for which LBT has been successful. When a communication device performs LBT on a certain sub-band, it determines whether LBT succeeds or fails by detecting the energy level on the sub-band. Under the condition of successful LBT, the energy detection value of a sub-band is smaller than a threshold, and the smaller the energy detection value of a certain sub-band during LBT is, the smaller the total power of an interference signal plus a noise signal on the sub-band is, and the smaller the interference suffered by the message when the message is transmitted on the sub-band is.

And in the third selection mode, the communication device selects the sub-band used by the received message from the sub-bands successful in the LBT, and if the sub-band used by the received message is not included in the sub-bands successful in the LBT, one sub-band is selected from the sub-bands successful in the LBT according to the first selection mode, the second selection mode or the fourth selection mode. In a TDD scenario, the sub-band used by the communication device to receive the message is sub-band 1, the sub-band for which LBT was successful includes sub-band 1, then the communication device selects sub-band 1 to send the message. For example, the sub-band used by the first communication device to receive the random access configuration information is sub-band 1, when the first communication device needs to transmit the random access preamble, LBT is performed on a plurality of sub-bands, and the sub-band where LBT succeeds includes sub-band 1, then the first communication device selects sub-band 1 to transmit the random access preamble. For another example, the sub-band used by the second communication device to receive the random access preamble is sub-band 2, when the second communication device needs to send the random access response message, LBT is performed on a plurality of sub-bands, and the sub-band where LBT succeeds includes sub-band 2, so that the second communication device selects sub-band 2 to send the random access preamble.

In the fourth selection mode, the communication apparatus randomly selects one subband from the subbands in which LBT succeeds.

Step S401 is described below:

the first communication device may select a first uplink subband from the uplink subbands with successful LBT among M or M1 uplink subbands according to the selection mode one, the selection mode two, the selection mode three, or the selection mode four, where the downlink subband corresponding to the first uplink subband is the first downlink subband.

Step S402 is described below:

and the second communication device sends a random access response message to the first communication device through the second downlink sub-band under the condition of detecting the random access preamble sent by the first communication device.

The second communications device may select the second downlink subband from the N or N1 downlink subbands in accordance with the first selection mode, the second selection mode, the third selection mode, or the fourth selection mode. The uplink sub-band corresponding to the second downlink sub-band is a second uplink sub-band, and the number of the second uplink sub-band is one or two.

The random access response message is used to indicate uplink resource allocation information of K1 uplink subbands in the M uplink subbands, that is, indicate that the second communication device allocates uplink resources of K1 uplink subbands to the first communication device.

Step S403 is described as follows:

in one example, the first communications device performs LBT on K1 uplink subbands according to uplink resource allocation information of K1 uplink subbands indicated by the random access response message, determines a third uplink subband from K1 uplink subbands, and sends a message three to the second communications device through the third uplink subband.

Wherein the third message carries the identification information of the first communication device, and the identification information may be C-RNTI, or S-TMSI or a random number.

The first communication device may select a third uplink subband from the uplink subbands successful in LBT among the K1 uplink subbands according to the first selection mode, the second selection mode, the third selection mode, or the fourth selection mode, where a downlink subband corresponding to the third uplink subband is the third downlink subband.

Step S404 is described below:

and the second communication device sends a competition resolving message to the first communication device through the fourth downlink sub-band under the condition that the third message is received, namely the second communication device successfully decodes the third message, wherein the competition resolving message carries the identification information of the first communication device.

In one example, the second communication device interacts information with the core network device and executes a corresponding function when receiving the third message, and sends a contention resolution message to the first communication device through the fourth downlink sub-band after the interaction is completed.

The first communication device detects whether the identification information carried by the competition resolving message is the same as the identification information carried by the message three or not under the condition of receiving the competition resolving message, and if so, the first communication device successfully competes for random access; if not, the first communication device is unsuccessful in competing random access.

The second communications device may select the fourth downlink subband from the N or N1 downlink subbands in accordance with the selection mode one, the selection mode two, the selection mode three, or the selection mode four. The uplink sub-band corresponding to the fourth downlink sub-band is a fourth uplink sub-band, and the number of the fourth uplink sub-band is one or two.

When the second communication apparatus does not receive the third message from the first communication apparatus (the second communication apparatus may not receive the third message within the timer time, or the second communication apparatus fails to decode the third message), the second communication apparatus transmits the third message retransmission scheduling message to the first communication apparatus. The message three retransmission scheduling message is used to indicate uplink resource allocation information of K2 uplink subbands among the M uplink subbands, that is, to indicate uplink resources of K2 uplink subbands allocated by the second communication device to the first communication device. It can be understood that, in the case that the second communication apparatus does not receive the message three from the first communication apparatus, the second communication apparatus transmits a message three retransmission scheduling message, and the second communication apparatus may schedule K2 uplink subbands with a higher idle ratio among the M uplink subbands to the first communication apparatus according to the updated ratio at which the channel on each downlink subband is detected to be idle and busy. One uplink subband of the K2 uplink subbands is used for the first communication device to retransmit message three.

And the first communication device performs LBT on K2 uplink sub-bands according to the uplink resource allocation information of K2 uplink sub-bands indicated by the message three retransmission scheduling message under the condition of receiving the message three retransmission scheduling message, determines one uplink sub-band from the K2 uplink sub-bands, and retransmits the message three to the second communication device through the uplink sub-band, namely retransmits the message three.

Wherein K1 is not more than K2. The second communication device can improve the LBT success rate on a plurality of uplink sub-bands by increasing the number of the uplink sub-bands for transmitting the scheduling message three, and improve the success probability of message three retransmission.

And if the second communication device still does not receive the message III retransmitted by the first communication device, the second communication device sends the message III retransmission scheduling message to the first communication device again. The message three retransmission scheduling message is used to indicate uplink resource allocation information of K3 uplink subbands among the M uplink subbands, that is, to indicate uplink resources of K3 uplink subbands allocated by the second communication device to the first communication device. For example, K2 ≦ K3. And the first communication device performs LBT on K3 uplink sub-bands according to the uplink resource allocation information of K3 uplink sub-bands indicated by the message three retransmission scheduling message under the condition of receiving the message three retransmission scheduling message, determines one uplink sub-band from the K3 uplink sub-bands, and retransmits the message three to the second communication device through the uplink sub-band. And repeating the steps until the sending times of the message triple transmission scheduling message reach the maximum retransmission scheduling times.

The scheduling message is retransmitted through the message three, which is beneficial to improving the probability that the second communication device successfully receives the message three.

In one example, the third uplink sub-band is different from the first uplink sub-band, that is, the first communication device transmits the random access preamble and the message three through different uplink sub-bands. Compared with the situation that the random access lead code and the message III are sent on the same uplink sub-band, the LBT success rate is improved, the time consumption of the random access process can be further shortened, and the efficiency of the random access process can be improved.

In an example, at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band, that is, the second downlink sub-band is different from the first downlink sub-band, or the fourth downlink sub-band is different from the first downlink sub-band, or the second downlink sub-band and the fourth downlink sub-band are different from the first downlink sub-band. In other words, at least one of the downlink sub-band occupied by the second communication device for transmitting the random access response message and the downlink sub-band occupied by the second communication device for transmitting the contention resolution message is different from the first downlink sub-band. Compared with the situation that the random access response message and the competition resolving message are sent on the downlink sub-band corresponding to the uplink sub-band occupied by the random access lead code and the random access message, the LBT success rate is improved, the time consumption of the random access process can be further shortened, and the efficiency of the random access process can be improved.

In one example, the third uplink sub-band is different from the first uplink sub-band, and at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band.

In the embodiment shown in fig. 4, each uplink message and each downlink message in the random access process are arranged on a plurality of subbands, so that the time consumption of the random access process can be reduced, and the efficiency of the random access process can be improved.

Fig. 5a is a schematic diagram of the embodiment shown in fig. 4 applied in a TDD scenario. The first communication device and the second communication device use resources on the sub-bands in a TDD manner, that is, the first communication device and the second communication device can transmit and receive messages on all the sub-bands in the TDD manner.

In fig. 5a, M ═ N ═ 4, and each uplink subband is the same subband as its corresponding downlink subband.

The second communication device performs LBT on sub-band 1, sub-band 2, sub-band 3, and sub-band 4, and broadcasts random access configuration information on sub-band 2 and sub-band 3 for which LBT is successful.

The first communication device LBT sub-band 1, sub-band 2, sub-band 3, and sub-band 4 upon receiving the random access configuration information, and transmits a random access preamble to the second communication device on sub-band 3 where LBT is successful. If there are multiple LBT successful subbands, the first communication device may select one of the multiple LBT successful subbands according to selection mode one, selection mode two, selection mode three, or selection mode four. If the third selection method is adopted, the sub-band used for receiving the random access configuration information is selected from the plurality of sub-bands with successful LBT.

The second communication apparatus LBT the sub-band 1, the sub-band 2, the sub-band 3, and the sub-band 4 upon receiving the random access preamble, and transmits a random access response message to the first communication apparatus on the sub-band 4 where LBT succeeds. If there are multiple LBT successful subbands, the second communications device may select one of the multiple LBT successful subbands according to selection mode one, selection mode two, selection mode three, or selection mode four. If the third selection method is adopted, the sub-band used for receiving the random access preamble is selected from the plurality of sub-bands with successful LBT. The random access response message includes time-frequency resources allocated for the first communication device to transmit message three.

After sending the random access preamble, the first communication device attempts to receive a random access response message on a sub-band 1, a sub-band 2, a sub-band 3 and a sub-band 4 according to a pre-configured random access response message receiving window, and if the first communication device does not receive the random access response message in the receiving window, the first communication device re-initiates a random access process; and if the first communication device receives the random access response message in the receiving window, performing LBT on the sub-band indicated by the random access response message, and sending a message III on the sub-band 4 with successful LBT. Subband 4 may be selected from one of the plurality of LBT successful subbands according to selection mode one, selection mode two, selection mode three, or selection mode four. Message three carries identification information of the first communication device.

And the second communication device performs LBT on the sub-band 1, the sub-band 2, the sub-band 3 and the sub-band 4 under the condition of receiving the message III, and transmits a competition resolving message on the sub-band 1 with successful LBT, wherein the competition resolving message carries identification information.

The first communication device detects whether the identification information carried by the competition resolving message is the same as the identification information carried by the message three or not under the condition of receiving the competition resolving message, and if so, the competition random access is successful; if not, the contention random access fails.

Fig. 5b is a schematic diagram of the embodiment shown in fig. 4 applied in an FDD scenario. The first communication device and the second communication device divide all sub-bands into an uplink sub-band and a downlink sub-band by adopting an FDD mode, and the first communication device and the second communication device use resources on the uplink sub-band [ uplink sub-band 1, uplink sub-band 2] and the downlink sub-band [ downlink sub-band 1, downlink sub-band 2] by adopting the FDD mode. In fig. 5b, M is 2 and N is 2.

The second communication device performs LBT on the 2 downlink sub-bands, and broadcasts the random access configuration information on the downlink sub-band 1 with successful LBT.

The first communication device performs LBT on 2 uplink sub-bands under the condition of receiving the random access configuration information, and sends a random access preamble to the second communication device on the uplink sub-band 2 where LBT succeeds. If there are multiple uplink subbands for which LBT is successful, the first communications device may select one uplink subband from the multiple uplink subbands for which LBT is successful according to selection mode one, selection mode two, or selection mode four.

And the second communication device performs LBT on the 2 downlink sub-bands under the condition of receiving the random access lead code, and sends a random access response message to the first communication device on the downlink sub-band 2 with successful LBT. If there are multiple downlink subbands successfully subjected to LBT, the second communications device may select one downlink subband from the multiple downlink subbands successfully subjected to LBT according to the first selection method, the second selection method, or the fourth selection method. The random access response message comprises time-frequency resources which are used for sending the message three and are distributed to the K1 uplink sub-bands of the first communication device, and K1 is less than or equal to M.

After sending the random access lead code, the first communication device tries to receive the random access response message on 2 downlink sub-bands according to a pre-configured random access response message receiving window, and if the first communication device does not receive the random access response message in the receiving window, the random access process is initiated again; if the first communication device receives the random access response message in the receiving window, LBT is performed on K1 uplink sub-bands indicated by the random access response message, and a message three is sent on uplink sub-band 1 where LBT succeeds. The uplink subband 1 may be one uplink subband selected by the first communication device from among the uplink subbands in which LBT is successful among the K1 uplink subbands according to the selection mode one, the selection mode two, or the selection mode four. Message three carries identification information of the first communication device.

And the second communication device performs LBT on the 2 downlink sub-bands under the condition of receiving the message III, and sends a competition resolving message on the downlink sub-band 2 with successful LBT, wherein the competition resolving message carries the identification information.

The first communication device detects whether the identification information carried by the competition resolving message is the same as the identification information carried by the message three or not under the condition of receiving the competition resolving message, and if so, the competition random access is successful; if not, the contention random access fails.

Fig. 4, 5a, and 5b are applied to the unlicensed spectrum scenario, and LBT is performed. For the scenario of the licensed spectrum, LBT may not be performed, for example, in fig. 4, the first communication device may select one uplink subband from M uplink subbands as a first uplink subband, and the second communication device may select one downlink subband from N downlink subbands as a second downlink subband; as another example, in fig. 5a, the first communication device may select one sub-band from 4 sub-bands to transmit the random access preamble, and the second communication device may select one sub-band from 4 sub-bands to transmit the random access response message. It can be understood that, in the scenario of the licensed spectrum, the first communication device may randomly select one uplink subband from the multiple uplink subbands to transmit the random access preamble or the random access message, and the second communication device may randomly select one downlink subband from the multiple downlink subbands to transmit the random access response message or the contention resolution message.

It is to be appreciated that in the unlicensed spectrum scenario, the communication device may select one subband for transmitting a message in accordance with selection mode one, selection mode two, selection mode three, or selection mode four. In the licensed spectrum scenario, the communication device may select one of the subbands from among the plurality of subbands for transmitting a message in two selection manners:

in the first selection mode', the communication apparatus selects one subband from the plurality of subbands with the same probability. E.g., 4 sub-bands, from which the communication device selects one sub-band with a probability of 1/4.

In the second selection method', the communication apparatus randomly selects one sub-band from a plurality of sub-bands.

The embodiment shown in fig. 4 will be further described below with 9 examples.

Example 1: M1K 1K 2 4N 1N 4 TDD unlicensed spectrum, and one option is selected

M1 ═ 4, the random access configuration information is used to indicate 4 uplink CCs [ CC1, CC2, CC3, CC4] of the 4 uplink CCs [ CC1, CC2, CC3, CC4] are used to transmit the random access preamble; n1 ═ 4, where the random access configuration information is used to indicate that 4 downlink CCs [ CC1, CC2, CC3, and CC4] of the 4 downlink CCs [ CC1, CC2, CC3, and CC4] are used to transmit a random access response message and a contention resolution message; the K1 ═ 4, the random access response message is used to indicate that the first communications device can transmit message three on the 4 uplink CCs CC1, CC2, CC3, CC 4.

The random access procedure based on example 1 is as follows:

(1) the first communication device receives the random access configuration information, knows that the random access preamble can be sent in 4 uplink CCs [ CC1, CC2, CC3 and CC4], and needs to monitor and receive the random access response message and the contention resolution message in 4 downlink CCs [ CC1, CC2, CC3 and CC4 ].

The first communication device performs LBT on 4 uplink CCs [ CC1, CC2, CC3 and CC4], the LBT is successful on CC1 and CC2, and a random access preamble is sent by selecting one of CC1 according to a selection mode, namely selecting CC1 to send the random access preamble according to 1/2 probability.

(2) The second communication device transmits a random access response message to the first communication device in a case where the random access preamble is received.

The second communication device performs LBT on 4 downlink CCs [ CC1, CC2, CC3, CC4], and after LBT succeeds on CC3 and CC4, selects CC4 in the selected mode to send a random access response message, where uplink resources allocated to the first communication device in the random access response message are used to indicate that the first communication device can send a message three on 4 CCs [ CC1, CC2, CC3, CC4 ].

(3) When the first communication apparatus has finished transmitting the random access preamble, it attempts to receive a random access response message on 4 downlink CCs CC1, CC2, CC3, and CC4, and receives the random access response message on CC 4. The first communication device will perform LBT on 4 uplink CCs CC1, CC2, CC3, CC 4.

Next, the first communication apparatus succeeds in LBT on CC1 and CC3, and selects CC3 among them to send message three in the selection mode one.

(4) After receiving the third message on CC3, the second communication apparatus performs LBT on 4 downlink CCs [ CC1, CC2, CC3, CC4], and selects CC4 to send a contention resolution message to the first communication apparatus if LBT succeeds on CC3, CC 4.

Example 2: m4, M1-3, K1-3, K2-4, N1-3, TDD, unlicensed spectrum, option two

M1 ═ 3, the random access configuration information is used to indicate that 3 uplink CCs [ CC1, CC2, CC4] of the 4 uplink CCs [ CC1, CC2, CC3, CC4] are used to transmit a random access preamble; n1 ═ 3, where the random access configuration information is used to indicate that 4 downlink CCs [ CC1, CC2, CC3, and CC4] of the 4 downlink CCs [ CC1, CC2, CC3, and CC4] are used to transmit a random access response message and a contention resolution message; the random access response message, K1 ═ 3, indicates that the first communications device can transmit message three on 3 uplink CCs CC1, CC2, CC 4.

The random access procedure based on example 2 is different from the random access procedure based on example 1 in the following points, and the rest of the same parts can be referred to the detailed description of the random access procedure based on example 1.

a, selecting the CCs in different manners, in example 2, selecting one CC from CCs with successful LBT according to a second selection manner;

b, in example 2, the first communications apparatus, upon receiving the random access configuration information, performs LBT on 3 uplink CCs [ CC1, CC2, CC4 ]; the first communication device performs LBT on 3 uplink CCs [ CC1, CC2, CC4] in case of receiving the random access response message;

c, in example 2, the second communications apparatus, upon receiving the random access preamble, performs LBT on 3 downlink CCs [ CC1, CC2, CC4 ]; the second communication device performs LBT on 3 downlink CCs [ CC1, CC2, CC4] when receiving the message three;

d, in example 2, the message three sent by the first communication apparatus cannot be received by the second communication apparatus due to interference in the wireless channel, the second communication apparatus does not receive the message three on [ CC1, CC2, CC4], the second communication apparatus performs LBT on [ CC1, CC2, CC4], and sends the message three retransmission scheduling message according to the selection mode two selection CC 4;

e, in example 2, after receiving the message three retransmission scheduling message, since the message three retransmission scheduling message indicates that K2 is 4, the first communication apparatus performs LBT on 4 uplink CCs [ CC1, CC2, CC3, CC4 ].

Example 3: m4, M1-3, K1-3, K2-2, N-4, N1-3, TDD, unlicensed spectrum, option two

M1 ═ 3, the random access configuration information is used to indicate that 3 uplink CCs [ CC1, CC2, CC4] of the 4 uplink CCs [ CC1, CC2, CC3, CC4] are used to transmit a random access preamble; n1 ═ 3, the random access configuration information is used to indicate that 3 downlink CCs [ CC1, CC2, CC4] of 4 downlink CCs [ CC1, CC2, CC3, CC4] are used to transmit a random access response message, a contention resolution message; the random access response message, K1 ═ 3, indicates that the first communications device can transmit message three on 3 uplink CCs CC1, CC2, CC 4.

The random access procedure based on example 3 is different from the random access procedure based on example 2 in that: in example 3, after receiving the message three retransmission scheduling message, the first communication apparatus performs LBT on 2 uplink CCs [ CC2, CC4] because the message three retransmission scheduling message indicates K2 is 2. The rest of the same parts can be seen in the detailed description of the random access procedure based on example 2.

Example 4: M1K 1K 2 4N 1N 4 TDD unlicensed spectrum, and selection method three

M1 ═ 4, the random access configuration information is used to indicate 4 uplink CCs [ CC1, CC2, CC3, CC4] of the 4 uplink CCs [ CC1, CC2, CC3, CC4] are used to transmit the random access preamble; n1 ═ 4, where the random access configuration information is used to indicate that 4 downlink CCs [ CC1, CC2, CC3, and CC4] of the 4 downlink CCs [ CC1, CC2, CC3, and CC4] are used to transmit a random access response message and a contention resolution message; the K1 ═ 4, the random access response message is used to indicate that the first communications device can transmit message three on the 4 uplink CCs CC1, CC2, CC3, CC 4.

The random access procedure based on example 4 is as follows:

(1) the first communications apparatus receives the random access configuration information from CC1 and CC3, and learns that the random access preamble can be sent in 4 uplink CCs [ CC1, CC2, CC3 and CC4], and that it needs to monitor and receive the random access response message and the contention resolution message in 4 downlink CCs [ CC1, CC2, CC3 and CC4 ].

The first communication device performs LBT on 4 uplink CCs [ CC1, CC2, CC3, CC4], and if LBT succeeds on CC1 and CC2, selects CC1 to send a random access preamble according to a selection mode, that is, CC1 satisfies both the condition that LBT is successfully selected and the condition that random access configuration information is received on CC 1.

(2) The second communication device transmits a random access response message to the first communication device in a case where the CC1 receives the random access preamble.

The second communication device performs LBT on 4 downlink CCs [ CC1, CC2, CC3, CC4], where LBT is successful on CC3 and CC4, and LBT is unsuccessful on CC1 where the second communication device receives the random access preamble, so that the second communication device selects CC4 from CC3 and CC4 to send a random access response message according to the first selection method, and uplink resources allocated to the first communication device in the random access response message are used to indicate that the first communication device can send a message three on 4 CCs.

(3) When the first communication apparatus has finished transmitting the random access preamble, it attempts to receive a random access response message on 4 downlink CCs CC1, CC2, CC3, and CC4, and receives the random access response message on CC 4. The first communication device will perform LBT on 4 uplink CCs CC1, CC2, CC3, CC 4.

Next, the first communication apparatus succeeds in LBT on CC1 and CC3, and selects CC3 among them to send message three in the selection mode one.

(4) After receiving the message three on the CC3, the second communication apparatus performs LBT on 4 downlink CCs [ CC1, CC2, CC3, CC4], and after LBT succeeds on CC3, CC4, selects CC3 for three times in a selection manner to send a contention resolution message to the first communication apparatus.

In the random access procedure according to example 4, the first communication apparatus selects one CC from CCs for which LBT succeeds in a selection manner, and transmits a random access preamble on the CC, which indicates that the first communication apparatus is idle on the CC. Since the second communication device sends the random access configuration information through the CC, which indicates that the channel of the second communication device on the CC is idle within a short period of time, and the channel of the second communication device on the CC is likely to be idle at the time when the first communication device sends the random access preamble, the first communication device selects the CC to send the random access preamble, which not only can ensure that the first communication device can successfully send the random access preamble, but also can improve the probability that the second communication device receives the random access preamble.

Example 5: m1, K1, K2, N1, 2, FDD, unlicensed spectrum, and one of the options is selected

M1 is 2, and the random access configuration information is used to indicate 2 uplink CCs [ uplink CC1, uplink CC2] of the 2 uplink CCs [ uplink CC1, uplink CC2] are used to transmit a random access preamble; n1 is 2, and the random access configuration information is used to indicate 2 downlink CCs [ downlink CC1, downlink CC2] of the 2 downlink CCs [ downlink CC1, downlink CC2] to be used to transmit a random access response message and a contention resolution message; the random access response message, K1 ═ 2, is used to indicate that the first communications device can transmit message three on 2 uplink CCs [ uplink CC1, uplink CC2 ].

The random access procedure based on example 5 is different from the random access procedure based on example 1 in that example 5 is applied in the scenario of FDD, and example 1 is applied in the scenario of TDD. The random access procedure based on example 5 can be seen from the description of fig. 5 b.

Example 6: m1, K1, K2, N1, 2, FDD, unlicensed spectrum, and option two

M1 is equal to 1, and the random access configuration information is used to indicate that 1 uplink CC [ uplink CC1] of the 1 uplink CC [ uplink CC1] is used to transmit a random access preamble; n1 is 2, and the random access configuration information is used to indicate 2 downlink CCs [ downlink CC1, downlink CC2] of the 2 downlink CCs [ downlink CC1, downlink CC2] to be used to transmit a random access response message and a contention resolution message; the random access response message, K1 ═ 1, indicates that the first communications device can transmit message three on 1 uplink CC [ uplink CC1 ].

The random access procedure based on example 6 is different from the random access procedure based on example 5 in that example 6 employs selection manner two, and example 5 employs selection manner one. Also, there is only one uplink CC [ uplink CC1] in example 6.

Example 7: M-M1-K1-K2-4, N-N1-4, TDD, licensed spectrum, and selecting one's mode'

The random access procedure based on example 7 is different from the random access procedure based on example 1 in that example 7 is applied to a scenario of licensed spectrum, and example 1 is applied to a scenario of unlicensed spectrum. In example 7, the first communications apparatus selects one uplink CC from 4 uplink CCs [ CC1, CC2, CC3, and CC4] to transmit the random access preamble in the first selection manner, and selects one uplink CC from 4 uplink CCs [ CC1, CC2, CC3, and CC4] to transmit the message three in the first selection manner; the second communication device selects one downlink CC from 4 downlink CCs [ CC1, CC2, CC3, CC4] to send a random access response message according to the first selection mode, and selects one downlink CC from 4 downlink CCs [ CC1, CC2, CC3, CC4] to send a contention resolution message according to the first selection mode. In other words, the first communication apparatus and the second communication apparatus do not perform LBT in the random access procedure based on example 7.

In the scenario of the licensed spectrum, when some of the 4 downlink subbands are occupied by some messages, which are more important than the random access response message or the contention resolution message, the second communication device may select one of the remaining subbands to transmit the random access response message or the contention resolution message.

Example 8: M-M1-K1-K2-2, N-N1-2, FDD, licensed spectrum, and select the mode one'

Example 8 there may be two first communication devices for which the random access procedure is as follows:

(1) when the first communication apparatus 1 and the first communication apparatus 2 receive the random access configuration information, both know that the random access preamble can be sent on 2 uplink CCs [ uplink CC1, uplink CC2], and need to monitor and receive the random access response message and contention resolution message on 2 downlink CCs [ downlink CC1, downlink CC2 ].

The first communication device 1 selects the uplink CC1 of the 2 uplink CCs [ uplink CC1, uplink CC2] according to the selection method one 'to transmit the random access preamble, and the first communication device 2 also selects the uplink CC1 according to the selection method one' to transmit the random access preamble.

The first communication apparatus 1 and the first communication apparatus 2 use the same time-frequency resource (e.g., (x2, y3), x2 represents the location of the time-domain resource, y3 represents the location of the frequency-domain resource) on the same uplink CC1 and a random access preamble with a preamble sequence R3. (typically there are multiple time-frequency resources (e.g., (x1, y1), (x2, y1), etc.) for random access preambles on a CC, and multiple preamble sequences (e.g., R1, R2, etc.))

(2) After the second communication device receives the preamble sequence R3 on the (x2, y3) time-frequency resource on the uplink CC1, the second communication device transmits a random access response message. Both the first communication apparatus 1 and the first communication apparatus 2 receive the random access response message.

When the first communication apparatus 1 and the first communication apparatus 2 simultaneously transmit the preamble sequence R3 using the (x2, y3) time-frequency resource on the CC1, the second communication apparatus receives the preamble sequence R3 on the (x2, y3) time-frequency resource on the uplink CC1, but the second communication apparatus cannot know that the random access preamble is the superposition of the random access preambles transmitted by the two first communication apparatuses, i.e. the second communication apparatus generally considers that the random access preamble comes from one first communication apparatus. The second communication device will send a random access response message in response to the first communication device, and it is understood that the random access response message sent by the second communication device is used to respond to the reception of the preamble sequence R3 on the (x2, y3) time frequency resource on the uplink CC 1.

(3) When the first communication apparatus 1 and the first communication apparatus 2 have transmitted the random access preamble, the random access response message is tried to be received on 2 downlink CCs [ downlink CC1, downlink CC2], and the random access response message is received on downlink CC 2. The first communication apparatus 1 and the first communication apparatus 2 both consider that the random access preamble transmitted for themselves according to the random access response message is a random access preamble (since the first communication apparatus 1 and the first communication apparatus 2 transmitted the preamble sequence R3 on the (x2, y3) time frequency resource on the uplink CC1, and the random access response message is used for responding to the reception of the preamble sequence R3 on the (x2, y3) time frequency resource on the uplink CC1), the first communication apparatus 1 and the first communication apparatus 2 both transmit the message three according to the information indicated by the random access response message.

Next, the first communication apparatus 1 selects the uplink CC1 of the third message in the first selection mode, and the first communication apparatus 2 selects the uplink CC2 of the third message in the first selection mode (it happens that the first communication apparatus 1 and the first communication apparatus 2 select different uplink CC transmission messages three).

(4) After receiving the two third messages on the uplink CC1 and the uplink CC2, the second communication device determines that two first communication devices have sent the same preamble sequence on the same random access preamble time-frequency resource. The second communication apparatus needs to indicate contention resolution information of the two first communication apparatuses in the contention resolution message and allocate different C-RNTIs to the two first communication apparatuses (normally, identification information of one first communication apparatus is indicated in the contention resolution message and TC-RNTI in the random access response message is upgraded to C-RNTI). That is, the contention resolution message includes at least two C-RNTIs, wherein each of the at least two C-RNTIs is an identity of one first communication apparatus.

The second communication device learns that there is no higher priority traffic on the 2 downlink CCs, selects the downlink CC2 to send the same contention resolution message indicating contention resolution information of the two first communication devices to the first communication device 1 and the first communication device 2 with the same probability on the 2 downlink CCs, and assigns different C-RNTIs to the two first communication devices.

So far, the random access of the two first communication devices is successful.

In the authorized spectrum scenario, when multiple first communication devices use the same time-frequency resource to transmit the same random access preamble to a second communication device and all consider that the random access response message is the random access preamble transmitted for themselves, the uplink resource indicated by the random access response message is used to transmit a third message, and when only one subband for transmitting the third message is used, the multiple first communication devices use the same subband to collide, and the second communication device can only successfully receive one (collision is not serious) or zero messages. In the embodiment of the application, in a scenario of authorized spectrum, the second communication device allocates K1 uplink sub-band transmission messages three to the first communication device, and sub-bands occupied by the multiple first communication devices for sending the messages three can be separated, so that the second communication device can successfully receive the multiple messages three, and the efficiency of the random access process is further improved.

Example 9: m2, M1 2, K1 1, K2 1, N2, N1 2, FDD, licensed spectrum + SUL

In the SUL scenario, two CC pairs are configured, that is, the auxiliary uplink CC may be one CC pair with the downlink CC1, and the high-frequency uplink CC may be one CC pair with the downlink CC 1.

M1 is 2, and the random access configuration information is used to indicate 2 uplink CCs [ auxiliary uplink CCs, high frequency uplink CCs ] for transmitting a random access preamble; n1 is 2, and the random access configuration information is used to indicate 2 downlink CCs [ downlink CC1, downlink CC2] for transmitting a random access response message and a contention resolution message; k1 ═ 1, the random access response message is used to indicate that the first communication device can transmit message three on 1 uplink CC.

The random access procedure based on example 9 is as follows:

(1) the first communication device receives the random access configuration information, learns that the random access preamble can be sent on the 2 uplink CCs, and needs to monitor and receive the random access response message and the contention resolution message on the 2 downlink CCs.

The first communication device selects the auxiliary uplink CC or the high frequency uplink CC according to the channel quality, that is, selects the high frequency uplink CC when the channel quality is good, and selects the auxiliary uplink CC when the channel quality is poor. Assume that the first communication device selects a high frequency uplink CC to transmit a random access preamble.

(2) The second communication device transmits a random access response message to the first communication device in a case where the random access preamble is received.

In 2 downlink CCs of the random access response message sent by the second communication device to the first communication device, 1 downlink CC (downlink CC1) is occupied by higher priority services (high reliability low delay service, emergency system broadcast information) and the like, the second communication device sends the random access response message on the rest downlink CC2, uplink resources allocated to the first communication device in the random access response message are used for indicating the first communication device to send a message III on a high frequency uplink CC (in a SUL scene, the random access lead code and the message III use the same type of uplink CC, namely, the random access lead code and the message III use the same or different high frequency uplink CC, or the random access lead code and the message III use the same or different auxiliary uplink CC, because the first communication device can select the high frequency uplink CC to send the random access lead code and the message III under the condition of good channel quality, the first communication device may select the secondary uplink CC to send the random access preamble and message three).

(3) When the first communication apparatus has finished transmitting the random access preamble, it attempts to receive a random access response message on 2 downlink CCs, and receives the random access response message on the downlink CC 2. The first communication device then sends message three on the high frequency uplink CC.

(4) After receiving the message three on the high-frequency uplink CC, the second communication apparatus selects the downlink CC1 on the 2 downlink CCs with the same probability without the higher priority service to send the contention resolution message to the first communication apparatus.

It should be noted that, the 9 examples are described by taking a carrier aggregation scenario as an example, and the 9 examples may also be applied to a scenario in which multiple BWPs exist in one cell in a 5G NR system.

The method of the embodiments of the present application is set forth above in detail and the apparatus of the embodiments of the present application is provided below.

Referring to fig. 6, which is a schematic diagram of a logical structure of a first communication device provided in the embodiment of the present application, the first communication device 60 may include a sending unit 601 and a receiving unit 602.

A sending unit 601, configured to send a random access preamble to a second communication apparatus through a first uplink subband in M uplink subbands of a multi-subband system;

a receiving unit 602, configured to receive a random access response message from a second communication device through a second downlink subband in N downlink subbands of a multi-subband system, where M and N are positive integers, and M >1 or N > 1;

a sending unit 601, further configured to send a third message to the second communication apparatus through a third uplink subband in the M uplink subbands, where the third message includes identification information of the first communication apparatus;

a receiving unit 602, further configured to receive a contention resolution message from the second communications apparatus through a fourth downlink subband of the N downlink subbands;

the downlink sub-band corresponding to the first uplink sub-band is a first downlink sub-band, the uplink sub-band corresponding to the second downlink sub-band is a second uplink sub-band, the downlink sub-band corresponding to the third uplink sub-band is a third downlink sub-band, and the uplink sub-band corresponding to the fourth downlink sub-band is a fourth uplink sub-band;

the first uplink sub-band, the third uplink sub-band, the first downlink sub-band, the second downlink sub-band and the fourth downlink sub-band at least satisfy one of the following conditions:

the third uplink sub-band is different from the first uplink sub-band; or the like, or, alternatively,

at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band.

In a possible implementation manner, the sending unit 802 is further configured to receive random access configuration information from the second communications apparatus, where the random access configuration information is used to indicate M1 uplink subbands among the M uplink subbands and N1 downlink subbands among the N downlink subbands, the M1 uplink subbands include a first uplink subband, and the N1 downlink subbands include a second downlink subband and a fourth downlink subband, where M1 is not greater than M, and N1 is not greater than N.

The M1 uplink subbands are candidate uplink subbands used for the first communication device to send the random access preamble, where the candidate uplink subbands refer to an uplink subband set selectable by the first communication device to send the random access preamble, and the uplink subband set may be used for the second communication device to detect and receive the random access preamble and the message three. That is, the first communication device may select one uplink sub-band from the candidate uplink sub-bands to transmit the random access preamble, and the second communication device may detect and receive the random access response message and the contention resolution message on all the candidate uplink sub-bands. The N1 downlink subbands are candidate downlink subbands used for the second communications apparatus to send the random access response message and the contention resolution message, where the candidate downlink subbands refer to a set of downlink subbands selectable for the second communications apparatus to send the random access response message and the contention resolution message, and the set of downlink subbands may be used for the first communications apparatus to detect and receive the random access response message and the contention resolution message. That is, the second communication apparatus may select one downlink sub-band from the candidate downlink sub-bands to transmit the random access response message, select one downlink sub-band from the candidate downlink sub-bands to transmit the contention resolution message, and the first communication apparatus may detect and receive the random access preamble and the message three on all the candidate downlink sub-bands.

In a possible implementation manner, the random access response message is used to indicate uplink resource allocation information of K1 uplink subbands in the M uplink subbands; the third uplink sub-band is one uplink sub-band of the K1 uplink sub-bands.

In a possible implementation manner, the receiving unit 602 is further configured to receive a message three retransmission scheduling message from the second communications apparatus, where the message three retransmission scheduling message is used to indicate uplink resource allocation information of K2 uplink subbands in the M uplink subbands;

the sending unit 601 is further configured to resend the message three to the second communication apparatus through one uplink subband in the K2 uplink subbands. Wherein K1 is not more than K2.

The transmitting unit 601 is configured to execute step S401 and step S403 in the embodiment shown in fig. 4, and the receiving unit 602 is configured to execute step S402 and step S404 in the embodiment shown in fig. 4.

The first communication device 60 shown in fig. 6 further includes a processing unit 603, configured to select a first uplink sub-band from M or M1 uplink sub-bands, so that the transmitting unit 601 transmits the random access preamble to the second communication device through the first uplink sub-band. The processing unit 603 is further configured to select a third uplink sub-band from the K1 uplink sub-bands, so that the sending unit 601 sends the message three to the second communication device through the third uplink sub-band.

Referring to fig. 7, which is a simplified schematic diagram of an entity structure of a first communication device according to an embodiment of the present application, the first communication device 70 includes a transceiver 701, a memory 703, and a processor 702. The transceiver 701, processor 702, and memory 703 may be interconnected by a bus 704, or may be connected in other ways. The related functions implemented by the transmitting unit 601 and the receiving unit 602 shown in fig. 6 may be implemented by the transceiver 701.

The memory 703 includes, but is not limited to, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or a portable read-only memory (CD-ROM), and the memory 703 is used for related instructions and data.

The transceiver 701 is used for transmitting data and/or signaling and for receiving data and/or signaling. In the embodiment of the present application, the first communication device communicates with the second communication device, sends the random access preamble and the third message to the second communication device, and receives the random access response message and the contention resolution message from the second communication device, that is, steps S401 to S404 in the embodiment shown in fig. 4 are performed.

The processor 702 may include one or more processors, such as one or more Central Processing Units (CPUs), and in the case that the processor 702 is one CPU, the CPU may be a single-core CPU or a multi-core CPU. In this embodiment, the processor 702 is configured to select a first uplink sub-band and a third uplink sub-band from M or M1 uplink sub-bands, so that the transceiver 701 transmits the random access preamble to the second communication device through the first uplink sub-band and transmits the message three to the second communication device through the third uplink sub-band.

The memory 703 is used to store program codes and data of the first communication device 70.

For the steps performed by the transceiver 701, reference may be specifically made to the description of the embodiment shown in fig. 4, which is not described herein again.

It will be appreciated that fig. 7 only shows a simplified design of the first communication device. In practical applications, the first communication device may further include necessary other elements, including but not limited to any number of transceivers, processors, controllers, memories, communication units, etc., respectively, and all devices that can implement the present application are within the protection scope of the present application.

Referring to fig. 8, which is a schematic diagram of a logic structure of a second communication apparatus provided in the embodiment of the present application, the second communication apparatus 80 may include a receiving unit 801 and a sending unit 802.

A receiving unit 801, configured to receive a random access preamble from a first communication device through a first uplink subband in M uplink subbands of a multi-subband system;

a sending unit 802, configured to send a random access response message to a first communication apparatus through a second downlink subband in N downlink subbands of a multi-subband system, where M and N are positive integers, and M >1 or N > 1;

a receiving unit 801, further configured to receive a third message from the first communication apparatus through a third uplink subband in the M uplink subbands, where the third message includes identification information of the first communication apparatus;

a sending unit 802, further configured to send a contention resolution message to the first communication apparatus through a fourth downlink subband in the N downlink subbands;

the downlink sub-band corresponding to the first uplink sub-band is a first downlink sub-band, the uplink sub-band corresponding to the second downlink sub-band is a second uplink sub-band, the downlink sub-band corresponding to the third uplink sub-band is a third downlink sub-band, and the uplink sub-band corresponding to the fourth downlink sub-band is a fourth uplink sub-band;

the first uplink sub-band, the third uplink sub-band, the first downlink sub-band, the second downlink sub-band and the fourth downlink sub-band at least satisfy one of the following conditions:

the third uplink sub-band is different from the first uplink sub-band; or the like, or, alternatively,

at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band.

In a possible implementation manner, the transmitting unit 802 is further configured to transmit, to the first communications apparatus, random access configuration information, where the random access configuration information is used to indicate M1 uplink subbands among the M uplink subbands and N1 downlink subbands among the N downlink subbands, the M1 uplink subbands include a first uplink subband, and the N1 downlink subbands include a second downlink subband and a fourth downlink subband, where M1 is greater than or equal to M, and N1 is greater than or equal to N.

The M1 uplink subbands are candidate uplink subbands used for the first communication device to send the random access preamble, where the candidate uplink subbands refer to an uplink subband set selectable by the first communication device to send the random access preamble, and the uplink subband set may be used for the second communication device to detect and receive the random access preamble and the message three. That is, the first communication device may select one uplink sub-band from the candidate uplink sub-bands to transmit the random access preamble, and the second communication device may detect and receive the random access response message and the contention resolution message on all the candidate uplink sub-bands. The N1 downlink subbands are candidate downlink subbands used for the second communications apparatus to send the random access response message and the contention resolution message, where the candidate downlink subbands refer to a set of downlink subbands selectable for the second communications apparatus to send the random access response message and the contention resolution message, and the set of downlink subbands may be used for the first communications apparatus to detect and receive the random access response message and the contention resolution message. That is, the second communication apparatus may select one downlink sub-band from the candidate downlink sub-bands to transmit the random access response message, select one downlink sub-band from the candidate downlink sub-bands to transmit the contention resolution message, and the first communication apparatus may detect and receive the random access preamble and the message three on all the candidate downlink sub-bands.

In a possible implementation manner, the random access response message is used to indicate uplink resource allocation information of K1 uplink subbands in the M uplink subbands; the third uplink sub-band is one uplink sub-band of the K1 uplink sub-bands.

In a possible implementation manner, if receiving unit 801 does not receive message three from the first communication apparatus, transmitting unit 802 is further configured to transmit a message three retransmission scheduling message to the first communication apparatus, where the message three retransmission scheduling message is used to indicate uplink resource allocation information of K2 uplink subbands in the M uplink subbands;

the receiving unit 801 is further configured to receive a retransmission of message three from the first communication apparatus through one uplink subband of the K2 uplink subbands. Wherein K1 is not more than K2.

The receiving unit 801 is configured to perform step S401 and step S403 in the embodiment shown in fig. 4, and the transmitting unit 802 is configured to perform step S402 and step S404 in the embodiment shown in fig. 4.

The second communication device 80 shown in fig. 8 further comprises a processing unit 803 for selecting a second downlink sub-band from the N or N1 downlink sub-bands, so that the transmitting unit 802 transmits the random access response message to the first communication device through the second downlink sub-band. The processing unit 603 is further configured to select a fourth downlink sub-band from the N or N1 downlink sub-bands, so that the transmitting unit 802 transmits the contention resolution message to the first communication device through the fourth downlink sub-band.

Referring to fig. 9, which is a simplified schematic diagram of an entity structure of a second communication device provided in the embodiment of the present application, the second communication device 90 includes a transceiver 901, a memory 903, and a processor 902. The transceiver 901, processor 902 and memory 903 may be interconnected via a bus 904, or may be connected in other ways. The relevant functions implemented by the receiving unit 801 and the transmitting unit 802 shown in fig. 8 may be implemented by the transceiver 901.

The memory 903 includes, but is not limited to, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or a portable read-only memory (CD-ROM), and the memory 903 is used for related instructions and data.

The transceiver 901 is used for transmitting data and/or signaling and for receiving data and/or signaling. In the embodiment of the present application, the first communication device communicates with the first communication device, receives the random access preamble and the message three from the first communication device, and sends the random access response message and the contention resolution message to the second communication device, that is, steps S401 to S404 in the embodiment shown in fig. 4 are performed.

The processor 902 may include one or more processors, such as one or more Central Processing Units (CPUs), and in the case that the processor 902 is one CPU, the CPU may be a single-core CPU or a multi-core CPU. In this embodiment, the processor 902 is configured to select a second downlink sub-band and a fourth downlink sub-band from N or N1 downlink sub-bands, so that the transceiver 901 sends the random access response message to the first communication device through the second downlink sub-band and sends the contention resolution message to the first communication device through the fourth downlink sub-band.

The memory 903 is used to store program codes and data of the second communication device 90.

For the steps performed by the transceiver 901, reference may be specifically made to the description of the embodiment shown in fig. 4, and details are not repeated here.

It will be appreciated that fig. 9 only shows a simplified design of the second communication means. In practical applications, the second communication device may also include necessary other components, including but not limited to any number of transceivers, processors, controllers, memories, communication units, etc., and all devices that can implement the present application are within the protection scope of the present application.

The embodiment of the application also provides a communication system which comprises at least one first communication device and at least one second communication device.

One of ordinary skill in the art will appreciate that all or part of the processes in the methods of the above embodiments may be implemented by hardware related to instructions of a computer program, which may be stored in a computer-readable storage medium, and when executed, may include the processes of the above method embodiments. And the aforementioned storage medium includes: various media capable of storing program codes, such as ROM or RAM, magnetic or optical disks, etc. Accordingly, a further embodiment of the present application provides a computer-readable storage medium having stored therein instructions, which, when executed on a computer, cause the computer to perform the method of the above aspects.

Yet another embodiment of the present application provides a computer program product containing instructions which, when run on a computer, cause the computer to perform the method of the above aspects.

Those of ordinary skill in the art would appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one unit.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in or transmitted over a computer-readable storage medium. The computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)), or wirelessly (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

Claims (26)

1. A random access method, comprising:

   the method comprises the steps that a first communication device sends a random access preamble to a second communication device through a first uplink sub-band in M uplink sub-bands of a multi-sub-band system;

   the first communication device receiving a random access response message from the second communication device through a second downlink sub-band of N downlink sub-bands of the multi-sub-band system, wherein M and N are positive integers, and M >1 or N > 1;

   the first communication device sends a third message to the second communication device through a third uplink sub-band in the M uplink sub-bands, wherein the third message comprises identification information of the first communication device;

   the first communication device receiving a contention resolution message from the second communication device through a fourth downlink sub-band of the N downlink sub-bands;

   the downlink sub-band corresponding to the first uplink sub-band is a first downlink sub-band, the uplink sub-band corresponding to the second downlink sub-band is a second uplink sub-band, the downlink sub-band corresponding to the third uplink sub-band is a third downlink sub-band, and the uplink sub-band corresponding to the fourth downlink sub-band is a fourth uplink sub-band;

   the first uplink sub-band, the third uplink sub-band, the first downlink sub-band, the second downlink sub-band and the fourth downlink sub-band at least satisfy one of the following conditions:

   the third uplink sub-band is different from the first uplink sub-band; or the like, or, alternatively,

   at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band.
2. The method of claim 1, wherein before the first communication device transmits the random access preamble to the second communication device via the first uplink subband of the M uplink subbands of the multi-subband system, further comprising:

   the first communications device receives random access configuration information from the second communications device, the random access configuration information indicating M1 uplink subbands among the M uplink subbands and N1 downlink subbands among the N downlink subbands, the M1 uplink subbands including the first uplink subband, the N1 downlink subbands including the second downlink subband and the fourth downlink subband, wherein M1 is greater than or equal to M, and N1 is greater than or equal to N.
3. The method of claim 2, wherein the M1 uplink sub-bands are candidate uplink sub-bands for the first communications device to send the random access preamble, and wherein the N1 downlink sub-bands are candidate downlink sub-bands for the second communications device to send the random access response message and the contention resolution message.
4. The method according to any of claims 1-3, wherein the random access response message is used to indicate uplink resource allocation information of K1 uplink sub-bands of the M uplink sub-bands; the third uplink sub-band is one uplink sub-band in the K1 uplink sub-bands.
5. The method of any of claims 1-4, wherein before the first communication device receives a contention resolution message from the second communication device via a fourth downlink sub-band of the N downlink sub-bands, after the first communication device sends a message three to the second communication device via a third uplink sub-band of the M uplink sub-bands, the method further comprises:

   the first communication device receiving a message three retransmission scheduling message from the second communication device, the message three retransmission scheduling message being used to indicate uplink resource allocation information of K2 uplink subbands among the M uplink subbands;

   the first communications device resends the message three to the second communications device through one of the K2 upstream subbands.
6. The method of claim 5, wherein K1 ≦ K2.
7. A random access method, comprising:

   the second communication device receives a random access preamble from the first communication device through a first uplink subband among M uplink subbands of the multi-subband system;

   the second communication device sends a random access response message to the first communication device through a second downlink sub-band of N downlink sub-bands of the multi-sub-band system, wherein M and N are positive integers, and M >1 or N > 1;

   receiving, by the second communication device, a third message from the first communication device via a third uplink subband of the M uplink subbands, the third message including identification information of the first communication device;

   the second communication device sends a contention resolution message to the first communication device through a fourth downlink subband of the N downlink subbands;

   the downlink sub-band corresponding to the first uplink sub-band is a first downlink sub-band, the uplink sub-band corresponding to the second downlink sub-band is a second uplink sub-band, the downlink sub-band corresponding to the third uplink sub-band is a third downlink sub-band, and the uplink sub-band corresponding to the fourth downlink sub-band is a fourth uplink sub-band;

   the first uplink sub-band, the third uplink sub-band, the first downlink sub-band, the second downlink sub-band and the fourth downlink sub-band at least satisfy one of the following conditions:

   the third uplink sub-band is different from the first uplink sub-band; or the like, or, alternatively,

   at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band.
8. The method of claim 7, wherein prior to the second communication device receiving the random access preamble from the first communication device via a first uplink subband of the M uplink subbands of the multi-subband system, the method further comprises:

   the second communications device sends random access configuration information to the first communications device, where the random access configuration information indicates M1 uplink subbands among the M uplink subbands and N1 downlink subbands among the N downlink subbands, the M1 uplink subbands include the first uplink subband, and the N1 downlink subbands include the second downlink subband and the fourth downlink subband, where M1 is equal to or less than M, and N1 is equal to or less than N.
9. The method of claim 8, wherein the M1 uplink sub-bands are candidate uplink sub-bands for the first communications device to send the random access preamble, and wherein the N1 downlink sub-bands are candidate downlink sub-bands for the second communications device to send the random access response message and the contention resolution message.
10. The method according to any of claims 7-9, wherein the random access response message is used to indicate uplink resource allocation information of K1 uplink sub-bands of the M uplink sub-bands; the third uplink sub-band is one uplink sub-band in the K1 uplink sub-bands.
11. The method according to any one of claims 7-10, further comprising:

    if the second communication device does not receive the message three from the first communication device, sending a message three retransmission scheduling message to the first communication device, where the message three retransmission scheduling message is used to indicate uplink resource allocation information of K2 uplink subbands in the M uplink subbands;

    the second communication device receives a retransmission of the message three from the first communication device over one of the K2 uplink subbands.
12. The method of claim 11, wherein K1 ≦ K2.
13. A first communications device, comprising:

    a transmitting unit configured to transmit a random access preamble to a second communication device through a first uplink subband among M uplink subbands of a multi-subband system;

    a receiving unit, configured to receive a random access response message from the second communication device through a second downlink subband in N downlink subbands of the multi-subband system, where M and N are positive integers and M >1 or N > 1;

    the sending unit is further configured to send a third message to the second communication device through a third uplink subband in the M uplink subbands, where the third message includes identification information of the first communication device;

    the receiving unit is further configured to receive a contention resolution message from the second communications apparatus through a fourth downlink subband of the N downlink subbands;

    the downlink sub-band corresponding to the first uplink sub-band is a first downlink sub-band, the uplink sub-band corresponding to the second downlink sub-band is a second uplink sub-band, the downlink sub-band corresponding to the third uplink sub-band is a third downlink sub-band, and the uplink sub-band corresponding to the fourth downlink sub-band is a fourth uplink sub-band;

    the first uplink sub-band, the third uplink sub-band, the first downlink sub-band, the second downlink sub-band and the fourth downlink sub-band at least satisfy one of the following conditions:

    the third uplink sub-band is different from the first uplink sub-band; or the like, or, alternatively,

    at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band.
14. The first communication device of claim 13,

    the receiving unit is further configured to receive random access configuration information from the second communications apparatus, where the random access configuration information is used to indicate M1 uplink subbands from among the M uplink subbands and N1 downlink subbands from among the N downlink subbands, the M1 uplink subbands include the first uplink subband, and the N1 downlink subbands include the second downlink subband and the fourth downlink subband, where M1 is not greater than M, and N1 is not greater than N.
15. The first communications device of claim 14, wherein the M1 uplink subbands are candidate uplink subbands for the first communications device to transmit the random access preamble, and wherein the N1 downlink subbands are candidate downlink subbands for the second communications device to transmit the random access response message and the contention resolution message.
16. The first communications device according to any one of claims 13-15, wherein the random access response message is configured to indicate uplink resource allocation information of K1 uplink sub-bands of the M uplink sub-bands; the third uplink sub-band is one uplink sub-band in the K1 uplink sub-bands.
17. The first communication device according to any of claims 13-16,

    the receiving unit is further configured to receive a message three retransmission scheduling message from the second communications apparatus, where the message three retransmission scheduling message is used to indicate uplink resource allocation information of K2 uplink subbands in the M uplink subbands;

    the sending unit is further configured to resend the third message to the second communication device through one uplink subband in the K2 uplink subbands.
18. The first communications device of claim 17, wherein K1 ≦ K2.
19. A second communications device, comprising:

    a receiving unit, configured to receive a random access preamble from a first communication device through a first uplink subband among M uplink subbands of a multi-subband system;

    a sending unit, configured to send a random access response message to the first communication device through a second downlink subband in N downlink subbands of the multi-subband system, where M and N are positive integers, and M >1 or N > 1;

    the receiving unit is further configured to receive a third message from the first communication apparatus through a third uplink subband in the M uplink subbands, where the third message includes identification information of the first communication apparatus;

    the sending unit is further configured to send a contention resolution message to the first communication apparatus through a fourth downlink subband of the N downlink subbands;

    the downlink sub-band corresponding to the first uplink sub-band is a first downlink sub-band, the uplink sub-band corresponding to the second downlink sub-band is a second uplink sub-band, the downlink sub-band corresponding to the third uplink sub-band is a third downlink sub-band, and the uplink sub-band corresponding to the fourth downlink sub-band is a fourth uplink sub-band;

    the first uplink sub-band, the third uplink sub-band, the first downlink sub-band, the second downlink sub-band and the fourth downlink sub-band at least satisfy one of the following conditions:

    the third uplink sub-band is different from the first uplink sub-band; or the like, or, alternatively,

    at least one of the second downlink sub-band and the fourth downlink sub-band is different from the first downlink sub-band.
20. The second communication device of claim 19,

    the transmitting unit is further configured to transmit random access configuration information to the first communications apparatus, where the random access configuration information is used to indicate M1 uplink subbands from the M uplink subbands and N1 downlink subbands from the N downlink subbands, the M1 uplink subbands include the first uplink subband, and the N1 downlink subbands include the second downlink subband and the fourth downlink subband, where M1 is not greater than M, and N1 is not greater than N.
21. The second communications device of claim 20, wherein the M1 uplink subbands are candidate uplink subbands for the first communications device to transmit the random access preamble, and wherein the N1 downlink subbands are candidate downlink subbands for the second communications device to transmit the random access response message and the contention resolution message.
22. The second communications device according to any one of claims 19-21, wherein the random access response message is used to indicate uplink resource allocation information of K1 uplink sub-bands of the M uplink sub-bands; the third uplink sub-band is one uplink sub-band in the K1 uplink sub-bands.
23. The second communication device according to any one of claims 19 to 22,

    the sending unit is further configured to send a message three retransmission scheduling message to the first communication device if the receiving unit does not receive the message three from the first communication device, where the message three retransmission scheduling message is used to indicate uplink resource allocation information of K2 uplink subbands in the M uplink subbands;

    the receiving unit is further configured to receive a retransmission of the message three from the first communication device through one of the K2 uplink subbands.
24. The second communication device of claim 23, wherein K1 ≦ K2.
25. A computer-readable storage medium, characterized in that the computer storage medium stores a computer program comprising program instructions that, when executed by a module, cause the module to perform the method according to any one of claims 1-6.
26. A computer-readable storage medium, characterized in that the computer storage medium stores a computer program comprising program instructions that, when executed by a module, cause the module to perform the method according to any one of claims 7-12.

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