JP2018170621A - Radio communication device and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device that can map transmission data to a plurality of frequency bands, adjust transmission timing, and perform data transmission in the case of concurrent communication at a plurality of frequency bands separated from each other.SOLUTION: A transmission device 1000 uses a plurality of radio channels about which random access control is performed at each of a plurality of frequency bands separated from each other and transmits a signal. A channel utilization state observation unit 1060 observes a channel utilization state at a slot commonly synchronized at the frequency bands. An access control unit 1000 controls a digital signal processing unit and a high frequency processing unit and transmits pieces of partial data as packets for the respective frequency bands via the radio channels at the same timing in synchronization.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a wireless communication apparatus and a wireless communication method.

  Conventional wireless communication systems such as LTE (Long Term Evolution) Release 8 (Rel-8), which is a wireless communication system standardized by 3GPP (3rd Generation Partnership Project), communicate using a bandwidth of up to 20 MHz. Can be done.

  Furthermore, LTE-A (Long Term Evolution-Advanced), which is an advanced version of LTE, has a basic unit of bandwidth supported by LTE in order to achieve higher speed transmission while ensuring backward compatibility with LTE. Carrier aggregation (CA) technology that uses a plurality of component carriers (CC) bundled at the same time is adopted, and wideband transmission of 100 MHz width can be realized using 5 CC (100 MHz width) at the maximum. However, such carrier aggregation is transmission using different channels in adjacent frequency bands.

  Although speeding up as described above has been achieved, in recent years, the demand for mobile communication traffic has increased rapidly with the spread of highly functional mobile terminals such as smartphones.

  As a result, in addition to the expansion of the use of the conventional wireless LAN (Local Area Network), offload to the wireless LAN has progressed due to the increase in mobile data traffic due to the spread of smartphones, and the license-free band (2.4 GHz band, 5 GHz band ) Traffic has increased rapidly.

  In addition, due to the progress of IoT (Internet Of Things) / M2M (Machine to Machine) society, there are concerns about further tightening of the above frequency band and 920 MHz band, and improving the frequency utilization efficiency of these frequency bands is an urgent issue Yes.

  Here, since the usage status of radio resources varies depending on time, place, frequency band, radio channel, and the like, a situation in which only some frequency bands (or radio channels) are congested may occur.

  However, existing private wireless systems (for example, IEEE 802.11 wireless LAN) use a single frequency band or perform communication after determining one band to be used in advance. For example, IEEE802.11n is used after setting which of 2.4 GHz band and 5 GHz band is used. For this reason, there is a possibility that congestion may occur even when there is a vacant radio resource in the existing private wireless system as a whole.

  Here, cognitive radio technology is attracting attention in order to effectively use radio communication resources. The cognitive radio technology means that a wireless terminal recognizes the usage situation of surrounding radio waves and changes the radio communication resource to be used according to the situation. The cognitive radio technology includes a heterogeneous type in which different radio communication standards are selected and used according to a situation, and a frequency sharing type in which a radio terminal searches for a vacant frequency and secures a necessary communication band.

  In the heterogeneous type, the cognitive radio recognizes a plurality of radio systems operating in the vicinity, obtains information on the usage and feasible transmission quality of each system, and connects to an appropriate radio system. In other words, the heterogeneous cognitive radio indirectly increases the utilization efficiency of frequency resources by increasing the utilization efficiency of wireless systems existing in the vicinity.

  On the other hand, in the frequency sharing type, the cognitive radio has a frequency resource (this is called white space) that is not used temporarily or locally in a frequency band in which another radio system is operated. Is detected and signal transmission is performed using this. That is, the frequency sharing type cognitive radio directly increases the utilization efficiency of frequency resources in a certain frequency band.

  As a technique for solving the problem of the increase in traffic in the license-free band as described above, a plurality of wireless LAN standards (for example, 2.4 GHz band wireless LAN standard and 5 GHz band wireless LAN standard) having different usage frequency bands are used. A heterogeneous cognitive radio approach that can be selected or used in parallel can be considered (for example, Patent Document 1 and Patent Document 2).

  However, in this heterogeneous cognitive radio approach, it is necessary to divide transmission data as appropriate and assign in advance which frequency band to transmit. As a result, depending on the degree of congestion of each frequency band, problems such as transmission delays greatly differing depending on the used frequency band and the order in which data arrives at the destination are newly generated.

Therefore, it is desirable to realize cognitive wireless communication by sharing frequencies with existing systems in a plurality of frequency bands that are largely separated from each other, for example, 2.4 GHz band wireless LAN and 5 GHz band wireless LAN.
(Conventional wireless LAN collision avoidance technology)
Here, in a conventional wireless LAN, a technique called CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) is used to avoid collision of communication data in random access control.

  FIG. 11 is a conceptual diagram for explaining such a conventional CSMA / CA technique.

  In CSMA, before starting communication, it is confirmed by carrier sense whether there is a host that is currently communicating on a transmission medium (wireless channel), a plurality of hosts share the same transmission medium, and other hosts currently When there is no communication, multiple access is started to start communication.

  Here, if the wireless channel changes from the busy state to the idle state, generally communication becomes possible. However, if a plurality of hosts detect an idle state and start communication at the same time, a plurality of frames are transmitted at the same time, resulting in a collision.

  Therefore, in CSMA, the time from when the wireless channel is in an idle state to when transmission is possible is changed depending on the type of frame. By shortening the waiting time of frames with high priority, when a frame with low priority can be transmitted, the radio channel is busy due to frame transmission with high priority, and transmission is not executed. .

  Therefore, in CSMA, SIFS (Short IFS) and PIFS (Point Coordination Function IFS) are used as a waiting time (IFS: Inter Frame Space) until the radio channel changes from the busy state to the idle state and transmission of the next frame starts. , And three types of DIFS (Distributed Coordination Function IFS) are defined, and the length of the period becomes longer in the order of SIFS, PIFS, and DIFS. Generally, if transmission of a data frame is successful, it is necessary to always transmit a reception completion notification (ACK) immediately after that, so SIFS is assigned to ACK. On the other hand, DIFS is assigned to data frame transmission.

  However, in the case of data frame transmission, to be precise, after the busy state is changed to the idle state and the channel becomes free, the transmission waits for a certain period of time defined by DIFS, and further a random backoff time (contention window). It waits for transmission for the number of slots (called (CW)). The number of contention window slots to be waited on is randomly selected up to the contention window size. In this way, the terminal having the shortest waiting time can acquire the transmission right and transmit the frame.

  In addition to this, there is “RTS / CTS (Request to Send / Clear to Send)” devised for countermeasures against hidden terminals, for example, as a wireless LAN-specific access control mechanism. Here, the hidden terminal is a terminal that is out of the radio range from itself but is in the radio range of the communication partner. Although it cannot be known directly, it causes interference.

  Assuming that the reach of radio waves is Lm, consider a situation in which the communication partner B (access point) of the wireless terminal A is Lm ahead, and another wireless terminal C is further Lm ahead.

  At this time, since the radio wave of the terminal C does not reach the terminal A, the terminal C does not know the existence of the terminal C even if the terminal A checks whether another terminal is transmitting a signal (even if carrier sense is performed). It becomes a hidden terminal of terminal A. If no measures are taken, even if terminal C is transmitting to access point B, terminal A will also transmit data to access point B. This causes a collision at the access point B and causes a reduction in throughput.

  RTS / CTS is a mechanism in which all wireless devices send out an “RTS (transmission request)” packet before transmission and respond with “CTS (receivable)” if the receiving side can also receive the packet. In the above example, terminal C first transmits RTS to access point B. However, this RTS does not reach the terminal A.

  The access point B notifies the terminal C that it can be received by transmitting a CTS. Since this CTS also reaches the terminal A, the terminal A senses that communication will be performed, and postpones transmission. In the RTS / CTS packet, the channel occupation period is written, and communication is suspended during that time. This period is called “NAV (Network Allocation Vector)”.

JP 2011-111433 A JP 2013-187561 A

  However, when communicating in parallel in a plurality of frequency bands separated from each other, in order to perform random access control in a plurality of frequency bands, even if random backoff is performed in each of a plurality of channels in a plurality of bands, If backoff is not completed at the same time, there is a problem that a plurality of channels cannot be used together.

  The present invention has been made to solve the above-described problems, and its object is to transmit data to a plurality of frequency bands when communicating in a plurality of frequency bands separated from each other simultaneously. To provide a radio communication apparatus and a radio communication method capable of performing data transmission by mapping and adjusting the transmission timing of random access for each of a plurality of frequency bands.

  According to one aspect of the present invention, there is provided a wireless communication apparatus for transmitting a signal using a plurality of radio channels performing random access control in each of a plurality of frequency bands separated from each other, wherein transmission data Is divided into a plurality of partial data corresponding to each of a plurality of frequency bands, and a digital signal processing unit for generating a transmission packet for each frequency band and a digital signal corresponding to each frequency band are provided. Channel usage monitoring for observing the usage status of multiple radio channels in multiple frequency bands and multiple radio channel usage statuses in slots synchronized in common in multiple frequency bands. And the channel usage monitoring unit detect that a plurality of frequency bands are empty, and the digital signal processing unit and the high frequency Processor controls includes a plurality of radio channels, packets of each of a plurality of frequency bands including the partial data, respectively, and an access control unit to transmit at the same timing in synchronization.

  Preferably, the access control unit randomly sets a back-off time common to the plurality of frequency bands when it is detected that the plurality of frequency bands are free, and after the elapse of the back-off time, for each frequency band Are transmitted at the same timing in synchronization.

  Preferably, the access control unit i) randomly sets a back-off time in response to detecting that one of the plurality of frequency bands is free, starts counting of the back-off, ii) back If it is detected that another frequency band of the plurality of frequency bands is empty during the off period, the process is executed in synchronization with the back-off count in the other frequency band.

  Preferably, when the back-off count has expired, the access control unit is in a state where the frequency band targeted for back-off is empty, and the remaining frequency bands to be used for communication among the plurality of frequency bands Is busy, the frequency band targeted for backoff is set to transmission prohibited.

  Preferably, when the access control unit detects that the remaining frequency bands are in an empty state, the access control unit detects that all frequency bands to be used for communication are detected as empty states. Packets are transmitted synchronously at the same timing.

  According to another aspect of the present invention, there is provided a radio communication method for transmitting a signal using a plurality of radio channels performing random access control in each of a plurality of frequency bands separated from each other, wherein transmission data Is divided into a plurality of partial data corresponding to each of a plurality of frequency bands, a transmission packet is generated for each frequency band, and a digital signal is converted into a high-frequency signal for each corresponding frequency band for each frequency band. A step of converting, a step of observing a use situation of a plurality of radio channels in a plurality of frequency bands in a slot synchronized in common in the plurality of frequency bands, and a plurality of frequency bands being detected based on the observation. In response, the plurality of radio channels can respectively synchronize packets in each of a plurality of frequency bands each including partial data with the same timing. In and transmitting.

  According to the present invention, transmission data can be mapped to a plurality of frequency bands, and data transmission can be performed by adjusting the transmission timing of random access for each of the plurality of frequency bands.

It is a conceptual diagram for demonstrating the structure of the radio | wireless communications system of embodiment. It is a figure for demonstrating the specific example for mapping and transmitting transmission data to a several zone | band, and receiving and unifying collectively by the receiving side. It is a timing chart in the case of performing CSMA / CA control for each frequency band. 3 is a functional block diagram for explaining a configuration of transmitting apparatus 1000 according to Embodiment 1. FIG. It is a functional block diagram for demonstrating the example of a more detailed structure of the transmitter 1000. FIG. 3 is a timing chart for explaining access timing control according to the first embodiment; 10 is a flowchart for explaining operations of a channel usage state observation unit 1060 and an access control unit 1080. It is a functional block diagram for demonstrating the structure of the receiver 2000 of this Embodiment. 10 is a timing chart for explaining operations of a channel usage state observation unit 1060 and an access control unit 1080. 10 is a flowchart for explaining operations of a channel usage state observation unit 1060 and an access control unit 1080. It is a conceptual diagram for demonstrating the conventional CSMA / CA technique.

  Hereinafter, configurations of a wireless communication system and a wireless communication apparatus according to an embodiment of the present invention will be described. In the following embodiments, components and processing steps given the same reference numerals are the same or equivalent, and the description thereof will not be repeated unless necessary.

  In the following, as an example for explaining the receiving apparatus of the present invention, a plurality of existing unlicensed bands (for example, 920 MHz band used for IoT etc., 2 used for wireless LAN, which are largely separated from each other as described above). (.4 GHz band and 5 GHz band) will be described with reference to an example of a transmission apparatus in a wireless communication system capable of performing cognitive wireless communication by sharing a frequency with an existing system.

  However, the wireless communication apparatus of the present invention is not necessarily limited to such a case, and more generally, using a plurality of frequency bands separated from each other at the same time in synchronization with the same wireless method. The present invention can be applied to a transmission / reception device that performs communication. In addition, as will be described later, the wireless communication apparatus of the present invention may be applied to a transmission / reception apparatus that performs simultaneous and parallel communication at timings synchronized with different wireless systems using a plurality of frequency bands separated from each other. Is possible.

  Hereinafter, configurations of a wireless communication system and a wireless communication apparatus according to an embodiment of the present invention will be described. In the following embodiments, components and processing steps given the same reference numerals are the same or equivalent, and the description thereof will not be repeated unless necessary.

  In the following, as an example for explaining the transmission / reception apparatus of the present invention, a plurality of existing license-free bands (for example, 920 MHz band used for IoT etc., 2 used for wireless LAN, as described above) (.4 GHz band and 5 GHz band) will be described with reference to an example of a transmission / reception apparatus in a wireless communication system capable of performing cognitive wireless communication by sharing a frequency with an existing system.

  However, the wireless communication apparatus of the present invention is not necessarily limited to such a case, and more generally, using a plurality of frequency bands separated from each other at the same time in synchronization with the same wireless method. It is possible to apply to a receiving apparatus that performs communication. In addition, as will be described later, the wireless communication device of the present invention may be applied to a receiving device that performs communication in parallel at a timing synchronized by different wireless systems using a plurality of frequency bands separated from each other. Is possible.

  FIG. 1 is a conceptual diagram for explaining a configuration of a wireless communication system according to an embodiment.

  Referring to FIG. 1, on the assumption that the transmission side uses three frequency bands of 920 MHz band, 2.4 GHz band, and 5 GHz band, a transmission frame is assumed to use one radio channel in each band. Configure.

  In addition, although it is good also as using several channels in each frequency band, below, it demonstrates as what uses one channel for every frequency band.

  In the embodiment, radio access control having the following characteristics is performed.

  That is, first, on the transmission side, the usage status (such as availability of each radio channel) of a plurality of frequency bands is observed.

  Subsequently, the transmitting side transmits wireless packets (frames) at the same time using one or more unused frequency bands / radio channels. At this time, transmission data is mapped to a plurality of bands and transmitted.

  On the other hand, the receiving side collectively receives data from a plurality of bands and integrates the data.

  In such a transmission / reception, such a configuration can ensure a transmission opportunity even if there is a bias in the congestion situation between bands, so that it can be expected to improve frequency utilization efficiency and reduce transmission delay, and the data arrival order may be switched. There is no problem.

  FIG. 2 is a diagram for explaining a specific example for mapping transmission data to a plurality of bands, transmitting them in a lump, and receiving and integrating them on the receiving side.

  As shown in FIG. 2, the transmission data is divided by the number of symbols proportional to the transmission rate Ri of each band using the transmission sequence, and assigned to each band by serial / parallel conversion.

  For example, if (5 GHz band transmission rate: 2.4 GHz band transmission rate: 920 MHz band transmission rate) = (R1: R2: R3) = (3: 2: 1), the transmission data series is divided every 6 symbols, Three symbols, two symbols, and one symbol are allocated to the 5 GHz band (ch1), 2.4 GHz band (ch2), and 920 MHz band (ch3). Note that dividing and allocating a transmission sequence is not limited to such a case, and more generally, when m frequency bands are used, the ratio of frequency band transmission rates is set to (R1: R2). : ...: Rm) (assuming that the ratio is expressed as irreducible), the transmission sequence is divided into (R1 + R2 + ... + Rm) × n (m, n: natural number) symbols. R1 × n) symbols, (R2 × n) symbols,..., (Rm × n) symbols may be assigned.

  After such assignment, for each band, a physical header is attached to the transmission symbol to form a packet, and these packets are transmitted simultaneously and in parallel at the same timing.

  The number of symbols assigned to each band on the transmission side is stored as information in this physical header.

On the receiving side, synchronization and demodulation processing are performed using a physical header on each band. The demodulated sequences are combined by parallel / serial conversion in the reverse process of the transmission side, and the frame is decoded.
(Problem of controlling transmission timing by CSMA / CA for each frequency band)
As described above, the conventional CSMA / CA control was performed for each frequency band in performing simultaneous communication at the timing synchronized with the same wireless method using a plurality of frequency bands separated from each other. The problem of the case will be described.

  FIG. 3 is a timing chart in the case where CSMA / CA control is performed for each frequency band as described above.

  That is, in the configuration shown in FIG. 3, when idle in the radio band is detected by the CSMA / CA method, carrier sense is performed by backoff using DIFS and CW, and data is transmitted.

  However, since such a conventional CSMA / CA system operates for each frequency, it becomes impossible to perform carrier sensing in a plurality of frequency bands and to communicate data divided in parallel at the synchronized timing.

  Further, since the CW size is not necessarily set to an appropriate value in an environment with a lot of terminals and traffic, packet collisions may frequently occur.

  As described below, carrier sense and access timing control are executed.

  i) When detecting busy / idle in a plurality of frequency bands, a busy detection slot and two types of backoff slots are used in synchronization in a plurality of frequency bands.

  When it is determined that such a predetermined number of channels are idle, data is transmitted simultaneously.

  ii) Busy / idle of multiple frequencies is determined by carrier sense, channels that have been idle first are secured until a predetermined number of channels become idle, and data is transmitted after the predetermined number of channels are idle.

  With such a configuration, it is possible to effectively use the radio band and improve the transmission efficiency by using the minimum synchronous transmission processing.

Hereinafter, i) will be described as a first embodiment, and ii) will be described as a second embodiment.
(Embodiment 1)
[Configuration of transmitter]
FIG. 4 is a functional block diagram for explaining the configuration of transmitting apparatus 1000 according to the first embodiment.

  Referring to FIG. 4, transmission apparatus 1000 performs error correction coding section 1110 for performing error correction coding processing on transmission sequence data, and interleave processing for data after error correction coding. For the interleaving unit 1112 to be performed, the serial / parallel conversion (hereinafter referred to as S / P conversion) unit 1010 for performing processing assigned to each frequency band as described in FIG. 1, and the data after S / P conversion, Radio frame generation units 1020.1 to 1020.3 for executing digital processing for forming a radio frame (packet) for communication by a predetermined radio communication method, such as mapping processing and addition of a physical header, for each frequency band And digital-analog conversion processing and predetermined conversion for the digital signals from the radio frame generation units 1020.1 to 1020.3, respectively. RF processing units (RF units) 1040.1 to 1040.3 for performing modulation processing (for example, orthogonal modulation processing for a predetermined multi-level modulation method), up-conversion processing, power amplification processing, and the like, and RF And antennas 1050.1 to 1050.3 for transmitting the high-frequency signals of the sections 1040.1 to 1040.3, respectively. The operations of the RF units 1040.1 to 1040.3 are controlled based on a clock from a local oscillator 1030 provided in common to these units.

  In addition, about the modulation process performed by RF part 1040.1-1040.3, the modulation system and channel coding rate are prepared as a MCS table beforehand, and according to the communication situation of each frequency band, The MCS may be selected adaptively.

  Further, the transmission apparatus 1000 uses the reception function of the RF units 1040.1 to 1040.3 to use the usage status of each frequency band (one or more radio channels in each frequency band) (the availability status of each radio channel). And the like, and the processing timing of the radio frame generation units 1020.1 to 1020.3 and the transmission timing in the RF unit are controlled based on the observation of the channel usage monitoring unit 1060 and the channel usage monitoring unit 1060 And an access control unit 1080 which controls to transmit radio packets simultaneously in unused frequency bands and radio channels for a predetermined period at the same controlled transmission timing.

  Here, the channel usage state observation unit 1060 is configured to perform carrier sensing and channel sensing.

  Then, the access control unit 1080 selects and uses a channel that is determined to be usable according to the result of carrier sensing the target band that is a candidate at the time of transmission, and uses an unused frequency at the same controlled transmission timing. Wireless packets are transmitted simultaneously on the band / wireless channel.

  As described with reference to FIG. 2, the transmission apparatus 1000 configured as described above maps data to a plurality of bands and transmits the data in a lump, and the receiving side collectively receives the plurality of bands and integrates the data.

  FIG. 5 is a functional block diagram for explaining an example of a more detailed configuration of the transmission apparatus 1000.

  The functional block diagram shown in FIG. 5 shows, as an example, the configuration of a transmission device that conforms to a wireless communication scheme similar to the wireless communication standard 802.11a.

  That is, although the wireless communication standard 802.11a is a wireless LAN communication system of 5 GHz band, in FIG. 5, only the frequency band is different in the 2.4 GHz and 920 MHz bands. It shall be assumed that a transmitter conforming to is used.

  Therefore, in each frequency band, the configuration of the preamble portion of the packet is common to a plurality of frequency bands.

  However, it is not always necessary that the wireless communication system of each frequency band has the same configuration, even if the wireless communication system (signal format, symbol length, subcarrier interval, etc.) differs for each frequency band. Good. In this case, at least a single transmission sequence is divided into each band and transmitted at the same time, and the configuration of the RF section is basically the same except that the frequency bands are different, and the configuration of the preamble portion of the packet (Preamble length, etc.) may be different for each of a plurality of frequency bands.

  FIG. 5 exemplarily shows a configuration related to transmission in the 5 GHz band. Since a wireless communication system similar to the wireless communication standard 802.11a is assumed, a signal to be transmitted is subjected to OFDM (Orthogonal Frequency Division Multiplexing) modulation.

  Referring to FIG. 5, radio frame generation section 1020.3 receives transmission data distributed from S / P conversion section 1010 and executes mapping section 1122 for executing mapping processing and inverse Fourier transform processing. An IFFT unit 1130 for adding a guard interval, a GI adding unit 1140 for adding a guard interval portion, and a digital-analog converter (DAC) 1150 for converting a digital signal into an analog signal of an I component and a Q component.

  The high frequency processing unit 1040.3 includes a quadrature modulator 1210 for modulating a signal from the DAC 1150 into a predetermined multilevel modulation signal, an upconverter 1220 for upconverting the output of the quadrature modulator 1210, and an output of the upconverter 1220. And a power amplifier 1230 for amplifying and transmitting the signal from the antenna 1050.3.

  As a result, the baseband OFDM signal is converted into a carrier band OFDM signal by the RF unit 1040.3.

  Further, the high frequency processing unit 1040.3 is based on a clock frequency conversion unit 1310 for converting a reference frequency signal from the local oscillator 1030 into a reference clock signal in a corresponding frequency band, and a reference clock from the clock frequency conversion unit 1310. Based on the reference clock from the clock frequency conversion unit 1310 and the clock generation unit 1320 that generates the clock used for the modulation processing in the quadrature demodulator 1210, the clock used for the up-conversion processing in the up-converter 1220 is generated. Clock generation unit 1340.

  That is, the reference frequency signal from the local oscillator 1030 is used as a clock signal in the conversion from the baseband OFDM signal to the carrier band OFDM signal. More generally, even when the wireless communication systems are different, the reference frequency signal from the local oscillator 1030 is basically used as a clock signal in the conversion from the baseband signal to the carrier band signal.

  FIG. 6 is a timing chart for explaining the access timing control according to the first embodiment.

  FIG. 6 illustrates processing executed by the transmission apparatus 1000 of the terminal #x among a plurality of terminals that exist in the communication environment.

  For terminal #x, as shown in the lower part of FIG. 6, it is assumed that an initial interference wave exists in each frequency band (5 GHz band, 2.4 GHz band, 920 MHz band).

  Then, the channel usage state monitoring unit 1060 of the terminal #x detects the busy state of the corresponding frequency band in the time slot synchronized in each frequency band. Here, a time slot for detecting this busy state (the presence of an interference wave) is referred to as a “busy detection slot”. Although not particularly limited, for example, the “busy detection slot” is continuously repeated at intervals of 5 μs.

  Here, the “busy detection slot” is continuously repeated in order to detect an idle state in synchronization with a plurality of frequency bands, so that the reception state is kept until all the plurality of frequency bands are in an idle state. continue.

  In the example shown in FIG. 6, it is detected that the interference wave in the 2.4 GHz band disappears at time TA and the busy state is changed to the idle state. Similarly, in the 920 MHz band, at time TB, it is detected that the busy state has changed to the idle state at time TC in the 5 GHz band.

  When it is detected that the access control unit 1080 is in an idle state in all of the plurality of frequency bands, the access control unit 1080 performs back-off in synchronization with the plurality of frequency bands in common for a predetermined back-off slot time. To execute transmission.

  That is, at time TC, the access control unit 1080 switches back to the back-off slot, back-offs, performs carrier sense after the back-off, does not transmit by another terminal, and is in an idle state, the data Execute sending.

  Although there is no particular limitation, the back-off slot has a unit of, for example, a period of 9 μs, and the number of back-off slots is set at random. In FIG. 6, for example, the back-off is one slot. It shall be set.

  Further, in the above example, the case where transmission is performed using all three frequency bands has been described as an example. However, depending on the communication situation, two frequencies may be used, and the time for backoff may be increased from time TB. Switching to the slot may be used for back-off, or using one frequency, switching to the back-off slot may be used for back-off from time TA. It is assumed that the number of frequency bands to be used is determined in advance according to the communication status and the like before generating transmission data.

  FIG. 7 is a flowchart for explaining the operations of the channel usage state observation unit 1060 and the access control unit 1080 described in FIG.

  Referring to FIG. 7, when channel use state monitoring section 1060 detects that there is transmission data (S100), it performs carrier detection for busy detection in synchronization with a plurality of frequency bands (S102).

  When the channel usage monitoring unit 1060 detects that any one band is in an idle state (S104), the access control unit 108 determines whether to perform data transmission (S106). When a predetermined plurality of frequency bands are used and the idle state has not been reached up to a predetermined number of frequency bands (No in S106), the process returns to S102.

  When the access control unit 108 detects that all of a plurality of communication frequency bands are in an idle state, the access control unit 108 determines that data transmission is to be performed (Yes in S106), and switches to the back-off slot to perform back-off. It is executed for a randomly set period (S108), and when the back-off is completed (Yes in S108), carrier sense is executed, and if no other terminal is communicating (Yes in S110), data in multiple frequency bands Is divided and transmitted (S112). On the other hand, when carrier sense is executed and another terminal is communicating (No in S110), the process is returned to step S102.

  With such a configuration, busy / idle information in a plurality of frequency bands can be detected, so that data transmission can be performed simultaneously in a plurality of frequency bands.

Further, since busy detection can be performed for each frequency, simultaneous transmission in a plurality of frequency bands can be realized without synchronization (information sharing) using a beacon from an access point (base station) or the like.
(Receiver configuration)
Below, the structure of the receiver 2000 which receives the transmission signal from the transmitter 1000 demonstrated in FIG. 4 is demonstrated easily.

  FIG. 8 is a functional block diagram for explaining the configuration of receiving apparatus 2000 of the present embodiment.

  Referring to FIG. 8, receiving apparatus 2000 includes antennas 201. 1 to 200.3 and antennas 201. 1 for receiving signals in a plurality of frequency bands (920 MHz band, 2.4 GHz band, and 5 GHz band), respectively. Common to the receiving units 2100.1 to 2100.3 and the receiving units 2100.1 to 2100.3 for executing reception processing such as down-conversion processing, demodulation / decoding processing, etc. A local oscillator 2020 that generates a reference frequency signal that is a clock serving as a reference for the operation of the receiving units 2100.1 to 2100.3, and each sequence of signals from the receiving units 2100.1 to 2100.3 as a transmitting side. In the reverse process, a parallel / serial conversion unit 2700 for coupling by parallel / serial conversion is included.

  The output of the integrated frame from the parallel / serial (P / S) conversion unit 2700 is passed to the upper layer.

  The receiving device 2000 detects the frequency offset of the local oscillator 2020 from the received preamble signal, generates a signal (oscillation frequency control signal) for controlling the oscillation frequency of the local oscillator 2020, and performs carrier frequency synchronization processing. And a synchronization processing unit 2600 that generates a signal (synchronization timing signal) for timing synchronization in digital signal processing from the received signal.

  Receiving section 2100.1 receives the signal from antenna 2010.1, and performs low-noise amplification processing, down-conversion processing, demodulation processing for a predetermined modulation scheme (for example, orthogonal demodulation processing for a predetermined multilevel modulation scheme), analog A high-frequency processing unit (RF unit) 2400.1 for executing digital conversion processing and the like, and a baseband for executing baseband processing such as demodulation / decoding processing on the digital signal from the RF unit 2400.1 A processing unit 2500.1 is included.

  The receiving unit 2100.2 also includes a high frequency processing unit (RF unit) 2400.2 and a baseband processing unit 2500.2 for performing similar processing for the corresponding frequency band. The receiving unit 2100.3 also includes a high frequency processing unit (RF unit) 2400.3 and a baseband processing unit 2500.3 for performing similar processing for the corresponding frequency band.

  The baseband processing units 2500.1 to 2500.3 and the parallel / serial (P / S) conversion unit 2700 are collectively referred to as a digital signal processing unit 2800.

  The signal from the P / S conversion unit 2700 of the digital signal processing unit 2800 is deinterleaved by the deinterleaving unit 4042, and then error correction processing is executed by the error correction unit 4040. Although not particularly limited, for example, error correction using a convolutional code can be used as the error correction processing.

As described above, according to the configuration of transmitting apparatus 1000 of Embodiment 1, busy / idle information in a plurality of frequency bands can be detected, data can be transmitted simultaneously in a plurality of frequency bands, and a plurality of receiving apparatuses 2000 can perform data transmission. Bands can be received collectively to integrate data.
(Embodiment 2)
Hereinafter, another example of the operations of the channel usage state monitoring unit 1060 and the access control unit 1080 will be described.

  However, the configurations of transmitting apparatus 1000 and receiving apparatus 2000 are basically the same as those in the first embodiment except for the operations of channel utilization state observing section 1060 and access control section 1080 described above. Will not repeat.

  FIG. 9 is a timing chart for explaining the operations of the channel usage monitoring unit 1060 and the access control unit 1080 according to the second embodiment.

  FIG. 9 also shows processing executed by the transmitting apparatus 1000 of terminal #x among a plurality of existing terminals.

  For terminal #x, as shown in the lower part of FIG. 9, it is assumed that interference waves exist in each frequency band (5 GHz band, 2.4 GHz band, 920 MHz band).

  Then, the channel usage state monitoring unit 1060 of the terminal #x detects the busy state of the corresponding frequency band in the time slot synchronized in each frequency band. Again, the time slot for detecting this busy state (the presence of an interference wave) is called a “busy detection slot”. For example, the “busy detection slot” is continuously repeated at intervals of 5 μs. To do.

  Here, the “busy detection slot” is continuously repeated in order to detect the idle state in synchronization with a plurality of frequency bands, so that the reception state is changed until the corresponding frequency band is in the idle state. continue.

  In the example shown in FIG. 9, it is detected that the interference wave in the 2.4 GHz band disappears at the time TA, and the busy state is changed to the idle state.

  At this time, the access control unit 1080 sets a random back-off time for the 2.4 GHz band, and thereafter counts the time until the set back-off time elapses.

  In the example of FIG. 9, it is detected that the busy state has changed to the idle state at time TB even in the 920 MHz band. Therefore, the access control unit 1080 thereafter counts back-off in synchronization with the 2.4 GHz band and the 920 MHz band. Here, a slot for performing back-off synchronously before collective transmission in a plurality of frequency bands is referred to as a “pre-back-off slot”. Although there is no particular limitation, the period of the “previous backoff slot” is also set to 5 μs, and the number of the “previous backoff slot” is continuously counted until the initially set backoff time expires. To do.

  In the example of FIG. 9, the back-off time expires at time TB ′. At this time, in the 5 GHz band, the interference wave still exists and remains busy.

  Therefore, according to the detection result of the channel usage state monitoring unit 1060, the access control unit 1080 is in an idle state at the end of the backoff time in both the 2.4 GHz band and the 920 MHz band, and the transmission apparatus 1000 transmits If an opportunity can be obtained and the transmitter 1000 is set to perform batch transmission in three frequency bands, the 2.4 GHz band and 920 MHz are obtained until a transmission opportunity in the 5 GHz band is obtained. In order to secure the transmission opportunity already acquired in the band, the access control unit 1080 holds the 2.4 GHz band and the 920 MHz band in the transmission prohibited state. As a method for setting the transmission prohibited state, for example, a null data signal can be generated and transmitted for the 2.4 GHz band and the 920 MHz band to occupy the band. However, if the transmission prohibition method is a method for disabling transmission of other terminals, other methods such as notifying transmission prohibition by a control signal as a method similar to conventional RTS / CTS etc. It may be.

  Next, at time TC, when the channel usage state monitoring unit 1060 detects that the 5 GHz band has changed from the busy state to the idle state, the access control unit 1080 sets the transmission prohibited state between the 2.4 GHz band and the 920 MHz band. After confirming that these frequency bands are in the idle state in the period specified by the carrier sense slot in the 5 GHz band, 2.4 GHz band, and 920 MHz band, the divided data is transferred to multiple frequencies. Synchronize with the band and send all at once.

  FIG. 10 is a flowchart for explaining the operations of the channel use state observation unit 1060 and the access control unit 1080 described in FIG.

  Referring to FIG. 10, when channel usage state monitoring unit 1060 detects that there is transmission data (S200), it performs carrier detection for busy detection on a frequency band in which it is not detected that the idle state is detected. It implements synchronizing with multiple frequency bands (S202).

  The access control unit 1080 determines whether at least one idle state has been detected in a plurality of frequency bands, and if it has not detected an idle state in any of the plurality of frequency bands (No in S204). ), The process is returned to step S202. On the other hand, if at least one idle state has been detected in a plurality of frequency bands (Yes in S204), the access control unit 1080 then determines whether it is the detection of the first idle state (S206). ), When it is the detection of the first idle state (Yes in S206), the back-off time is set at random and the back-off counter is set (S208). On the other hand, if it is not the detection of the first idle state (No in S206), that is, if the idle state is detected even in a frequency band that is not the frequency band that first detected the idle state, The pre-backoff slot is also synchronized with the frequency band that is newly detected to be in the idle state (S212).

  Subsequently, the access control unit 1080 decrements the back-off counter by 1 (S214), and determines whether the back-off counter is 0 (S220). If the back-off counter is not 0 (No in S220), the process returns to step S202 to execute back-off for the frequency band in which the idle state is detected, and for the remaining frequency bands to be busy. Detection is performed.

  On the other hand, if the back-off counter is 0 (Yes in S220), the access control unit 1080 determines whether the back-off target frequency band is in a transmission prohibited state or an idle state (S222).

  When the frequency band to be backed off is neither the transmission prohibited state nor the idle state, the access control unit 1080 resets the detection history of the idle state on the assumption that the transmission opportunity has not been acquired after the backoff ( In step S224, the process returns to step S202.

  When the frequency band to be backed off is either the transmission prohibited state or the idle state, the access control unit 1080 subsequently determines whether to transmit in a plurality of frequency bands secured so far (S226). . If transmission is not performed only in the frequency band secured so far (No in S26), transmission of the frequency band to be backed off is prohibited (S228), and the process returns to step S202.

  On the other hand, when transmitting in the frequency band secured so far (Yes in S26), the access control unit 1080 cancels the transmission prohibition setting (S230), and uses the carrier sensing slot in the secured frequency bands. Carrier sense is executed (S232), and the divided data is transmitted in a lump in a plurality of frequency bands (S234).

  With the configuration as described above, it is possible to map each transmission data to a plurality of frequency bands in which random access control is performed, and to perform data transmission by adjusting the transmission timing. In that case, by using the minimum synchronous transmission processing, there is an effect of effectively using the radio band and improving the transmission efficiency.

  Embodiment disclosed this time is an illustration of the structure for implementing this invention concretely, Comprising: The technical scope of this invention is not restrict | limited. The technical scope of the present invention is shown not by the description of the embodiment but by the scope of the claims, and includes modifications within the wording and equivalent meanings of the scope of the claims. Is intended.

  1000 Transmitter, 1010 S / P converter, 1020.1 to 1020.3 Radio frame generator, 1030 Local oscillator, 1040.1 to 1040.3 RF unit, 1050.1 to 1050.3 Antenna, 1060 channel usage status Observation unit, 1080 access control unit, 1110 error correction coding unit, 1112 interleaving unit, 2000 receiving device, 2011-2010.3 antenna, 2020 local oscillator, 2100.1-2100.3 receiving unit, 2400.1 2400.3 RF section, 2500.1-2500.3 Baseband processing section, 2700 P / S conversion section, 2600 synchronization processing section, 2800 digital signal processing section, 4040 error correction section, 4042 deinterleave section.

Claims (6)

A wireless communication device for transmitting a signal using a plurality of wireless channels performing random access control in each of a plurality of frequency bands separated from each other,
A digital signal processing unit for dividing transmission data into a plurality of partial data corresponding to each of the plurality of frequency bands, and generating a transmission packet for each of the frequency bands;
A plurality of high-frequency signal processing units provided for each of the frequency bands, for converting the digital signal into a corresponding high-frequency signal for each frequency band;
A channel usage monitoring unit that monitors the usage status of the plurality of radio channels in the plurality of frequency bands in a slot synchronized in common with the plurality of frequency bands;
The digital signal processing unit and the high frequency processing unit are controlled in response to the channel usage state monitoring unit detecting that the plurality of frequency bands are vacant, and the partial data is transmitted by the plurality of radio channels. And an access control unit that transmits the packets for each of the plurality of frequency bands each including the same at the same timing.   The access control unit randomly sets a back-off time common to the plurality of frequency bands when the plurality of frequency bands are detected to be idle, and after the elapse of the back-off time, The wireless communication apparatus according to claim 1, wherein packets for each band are transmitted in synchronization at the same timing. The access control unit
i) In response to detecting that one of the plurality of frequency bands is in an empty state, a backoff time is randomly set, and a backoff count is started.
ii) If it is detected that another frequency band of the plurality of frequency bands is empty during the back-off period, execution is performed in synchronization with the back-off count in the other frequency band. The wireless communication device according to claim 1.   When the back-off count has expired, the access control unit is in a state where the frequency band targeted for back-off is empty, and the remaining frequencies to be used for communication among the plurality of frequency bands The radio communication apparatus according to claim 3, wherein when the band is busy, the frequency band targeted for back-off is set to be prohibited from transmission.   When the access control unit detects that all the frequency bands to be used for the communication are detected as being empty when it is detected that the remaining frequency bands are in an empty state, The wireless communication apparatus according to claim 3, wherein the packets are synchronously transmitted at the same timing. A wireless communication method for transmitting a signal using a plurality of wireless channels performing random access control in each of a plurality of frequency bands separated from each other,
Dividing transmission data into a plurality of partial data corresponding to each of the plurality of frequency bands, and generating a transmission packet for each of the frequency bands;
For each frequency band, converting the digital signal into a corresponding high frequency signal for each frequency band;
Observing the usage status of the plurality of radio channels in the plurality of frequency bands in slots synchronized in common in the plurality of frequency bands;
In response to detecting that the plurality of frequency bands are vacant based on the observation, the packets for the plurality of frequency bands each including the partial data are synchronized and identical by the plurality of wireless channels. And a step of transmitting at the timing.