0001]Technology disclosed herein relates to communication apparatus and communication method for performing packet transmission in a state where the detected interference signals (such as signals coming from adjacent cells).
BACKGROUND
[0002]In IEEE802.11, which is one of the representative standard of a wireless LAN, each terminal as a mechanism to acquire autonomously transmit opportunity, defines a CSMA / CA (Carrier Sense Multipe Access / Collision Avoidance). Specifically, the terminal transmits waits a random time period performs (backoff), the radio wave environment around during the back-off observed (Carrier Sense), a radio wave detection with more power than the detection threshold in stop the backoff when to suppress the transmission of packets. This backoff and carrier sense mechanism, the terminal while acquiring an autonomous distributed manner transmission opportunity, thereby avoiding packet collisions.
[0003]
　However, in an environment where many terminals exist at a high density, when the radio wave detection and collision avoidance described above using detection threshold that is set in the IEEE802.11 standard, the terminals belonging to, for example adjacent cells and the like thereby to detect the transmitted signal, the case of performing extra transmission suppression is seen as a problem. It is to be noted that the cell referred to herein is, for example, a base station configured with terminals under BSS: equivalent to (Basic Service Set Basic Service Set). Moreover, neighboring cells, other BSS (hereinafter, also referred to as "OBSS") that coverage overlap corresponds to.
[0004]
　Therefore, in a currently standardized IEEE802.11Ax, by reusing one frequency channel between adjacent cells, spatial reuse for using frequency resources efficiently (Spatial Reuse: SR) to consider technical It has been promoted. Specifically, the terminal between the adjacent cells also detect each other's signals, making it possible to perform transmission own packets. Such SR techniques describe an identifier of BSS simplified called "BSS Color" in the PHY header of the packet, it belongs on the basis of the BSS Color described in the PHY header at the receiving end BSS ( signal of the own cell) (hereinafter, the signal from also referred to as "own cell signal") and OBSS (neighboring cell) (hereinafter, are achieved by enabling the identification also called) and the "adjacent cell signal".
[0005]
　For example, a terminal that has received the packet, if it can be determined that a neighbor cell signal based on the description of the PHY header, abort reception of a packet at that time, further the received power is neighbor cell signal of the signal realizing spatial reuse by permitting the start of back-off equal to or less than the detection threshold (OBSS-PD threshold). In this manner, the terminal can be easily obtained a transmission opportunity by spatial reuse by can increase the OBSS-PD threshold by lowering the transmission power of its own, to adjust the transmit power in accordance with the interference power it is.
[0006]
　As another method of spatial reuse, the terminal obtains the information called SR parameter included in the neighbor cell signal packet, sets the transmission power so as not to affect the terminal belonging to the adjacent cell it has also been adopted it.
[0007]
　In this specification, the terminal (or the reception power in the neighbor cell signal, SR parameters listed in the packet) available information from the adjacent cell signal using, performed also backoff after the detection of the adjacent cell signal to send a packet Te, referred to as the "SR transmission".
CITATION
Patent Document
[0008]
Patent Document 1: JP 2013-179555 JP
Summary of the Invention
Problems that the Invention is to Solve
[0009]
　The purpose of the technology disclosed herein can be performed suitably packet transmission even when detects the signal from the neighboring cell is to provide an excellent communication device and communication method.
Means for Solving the Problems
[0010]
　Technology disclosed herein has been made in consideration of the above problems, a first aspect is
　a communication unit for transmitting a packet based on information about interference signal,
　the interference power or the transmission of the packet above until based on at least one of information related to the communication distance, and a control unit for controlling the transmission wait time in a state that observing the interference signal
is provided with a.
[0011]
　According to a second aspect of the technology disclosed herein, the control unit of the communication apparatus according to the first aspect, in accordance with at least one of information relating to the interference power or the communication distance, observe interference signals It is configured to select the parameters for determining a transmission latency in to that state.
[0012]
　According to a third aspect of the technology disclosed herein, the control unit of the communication apparatus according to the first aspect, as the interference power is high, or, as the communication distance is long, longer transmission wait time set, the higher the interference power is low, or, the higher the communication distance is short, is configured to set the shorter transmission wait time.
[0013]
　According to a fourth aspect of the technology disclosed herein, the control unit of the communication apparatus according to the first aspect, the transmission failure count when the transmitted packets based on the information about the interference signal, the interference It is configured to manage in association with the modes defined based on at least one of information related to the power or the communication distance.
[0014]
　According to a fifth aspect of the technology disclosed herein, the control unit of the communication apparatus according to the first aspect, a first transmission frequency of failures when transmitting a packet with no observed interference signal It is configured to manage separately a second transmission failure count when the transmitted packets based on information about interference signals.
[0015]
　According to a sixth aspect of the technology disclosed herein, in the communication apparatus according to the first aspect, information relating to the communication distance includes information relating to the propagation loss of the transmission destination .
[0016]
　Further, a seventh aspect of the technology disclosed herein,
　a communication step of transmitting the packet based on information about interference signals,
　on at least one of the interference power or information related to the distance to the destination of the packet based on, a control step for controlling the transmission wait time in a state that observing the interference signal
is a communication method having.
[0017]
　Further, an eighth aspect of the technology disclosed herein,
　a communication unit for transmitting a packet,
　and a control unit for controlling the transmission latency in transmitting a packet,
comprising a,
　wherein, the interference a first transmission latency in transmitting the packet with no observed signals, sets a transmission wait time plus additional latency,
which is a communication device.
[0018]
　According to a ninth aspect of the technology disclosed herein, the control unit of the communication apparatus according to the eighth aspect, in accordance with the result of sending a packet based on information about interference signals, the first It is configured to set a transmission wait time plus the additional latency in the transmission waiting time.
[0019]
　According to a tenth aspect of the technology disclosed herein, the control unit of the communication apparatus according to the eighth aspect is configured to set an additional waiting time based on information about interference signals.
[0020]
　Further, an eleventh aspect of the technology disclosed herein,
　a communication step of transmitting a packet,
　and a control step of controlling transmission latency in transmitting the packet,
has,
　in the control step, the interference a first transmission latency in transmitting the packet with no observed signals, sets a transmission wait time plus additional latency,
is a communication method.
[0021]
　Also, twelfth aspect of the technology disclosed herein,
　a control unit for controlling the transmission latency in state based on information about interference signals are observed interference signal of the communication partner can be a packet transmission,
　a notification unit for notifying the information for determining the transmission waiting time to the communication partner,
a communication device having a.
[0022]
　According to a thirteenth aspect of the technology disclosed herein, the notification unit of the communication apparatus according to a twelfth aspect of operates as an access point, packets transmitted based on the information about the interference signal under the control of possible to the terminal, and is configured to notify the information for determining the transmission waiting time.
[0023]
　According to a fourteenth aspect of the technology disclosed herein, in the communication apparatus according to a thirteenth aspect, the said information for determining the transmission waiting time, transmission waiting time in a state that observe interference signals it includes parameters for determining a.
[0024]
　According to a fifteenth aspect of the technology disclosed herein, in the communication apparatus according to a thirteenth aspect, the information for determining the transmission waiting time, when transmitting the packet in a state that does not observe interference signals it includes information specifying the presence or absence of additional latency for the transmission wait time.
[0025]
　According to a sixteenth aspect of the technology disclosed herein, in the communication apparatus according to the fifteenth aspect, the information for determining the transmission waiting time can further comprise information about values ​​of the additional waiting time there.
[0026]
　According to a seventeenth aspect of the technology disclosed herein, the association to the notification of the communication device according to the thirteenth aspect, the interference power or modes defined based on at least one of information regarding the communication distance Te, and it is configured to notify the information for determining the transmission waiting time.
[0027]
　According to a eighteenth aspect of the technology disclosed herein, the notification unit of the communication apparatus according to a thirteenth aspect of, based on the information regarding at least one of said terminal number or throughput of the terminal under wherein the control unit is set, it is configured to notify the information for determining the transmission waiting time.
[0028]
　Also, nineteenth aspect of the technology disclosed herein,
　a control step for controlling the transmission waiting time in the state based on the information about the interference signal is observing an interference signal in a communication partner capable of packet transmission,
　a notification step of notifying the information for determining the transmission waiting time to the communication partner,
a communication method having.
[0029]
　Also, twentieth aspect of the technology disclosed herein,
　a communication unit for transmitting and receiving a packet,
　and a control unit for controlling the transmission latency in transmitting a packet,
comprising a,
　the control unit, the based on the information described in the frame of the communication unit has received, it sets a transmission wait time in a state that observe interference signal,
which is a communication device.
Effect of the invention
[0030]
　According to the technique disclosed in this specification, even in a state that the detection signals from the adjacent cell, and appropriately adjusting the transmission waiting time, it is possible to perform the packet transmission, an excellent communication device and communication method it is possible to provide.
[0031]
　Note that the effect described herein is merely illustrative, the effect of the present invention is not limited thereto. Further, the present invention is, in addition to the above effects, in some cases exhibit a further additional effect.
[0032]
　Other objects, features and advantages of the technique disclosed herein, will become apparent from the following detailed description based on embodiments and the accompanying drawings described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033]
[1] Figure 1 is a diagram showing a configuration example of a wireless LAN system (Example 1).
FIG. 2 is a diagram schematically showing a functional configuration of a communication apparatus capable 200 to operate as an AP and STA.
FIG. 3 is a diagram showing a communication sequence example (when conventional back-off) in the wireless LAN system shown in FIG.
[4] FIG. 4 is a diagram showing a communication sequence example in a wireless LAN system shown in FIG. 1 (newly established SR backoff).
FIG. 5 is a flowchart communication device showing a processing procedure for setting the SR backoff (Example 1).
FIG. 6 is a diagram showing a configuration example of the SR mode selection table.
[7] FIG. 7 is a diagram showing a configuration example of a parameter setting table for each SR mode.
[8] FIG. 8 is a flowchart communication device showing a processing procedure performed after completion of the packet transmission (Example 1).
[9] FIG. 9 is a diagram showing a configuration example of a wireless LAN system (Example 2).
[10] FIG 10 is a diagram showing a communication sequence example in a wireless LAN system shown in FIG.
[11] FIG 11 is a diagram showing a communication sequence example in a wireless LAN system shown in FIG. 9 (Example 2).
[12] FIG 12 is a flowchart communication device showing a processing procedure performed after completion of the packet transmission (Example 2).
[13] FIG 13 is a diagram showing a configuration example of a frame used to notify a parameter used for adjusting SR backoff time.
DESCRIPTION OF THE INVENTION
[0034]
　It will be described in detail embodiments of the technology disclosed herein with reference to the drawings.
[0035]
　By allowing an SR transmission can mitigate excessive transmission suppression, each terminal it is possible to increase the transmission opportunity. However, on the other hand, the problem of interference level of the entire system by performing the SR transmission is increased occurs.
[0036]
　For example, when a certain terminal performs an SR transmission, the interference wave is mixed into the terminal receiving the packets of adjacent cell signal, deteriorating the communication quality of adjacent cells. On the other hand, in order to reduce the impact on the surrounding (interference amount), the case of obtaining a transmission opportunity by example, to suppress the transmission power as described above, turn lowers the reception power of a terminal that receives its own packet, the own cell But it leads to a deterioration of the communication quality.
[0037]
　Thus communication quality throughout the system is degraded, even if the increased transmission opportunity of the terminal, the throughput improvement of the entire system which may decrease.
[0038]
　Therefore, if the terminal is capable of performing the SR transmission there are multiple, far from the possible interference source (or interference source without affecting the periphery), and, close distance to the receiver ( or, sending its packet is not affected by interference) it is desirable that the terminal to acquire a transmission opportunity, the Applicants he believes.
[0039]
　However, at present, when the terminal is capable of performing the SR transmission there are multiple, which terminal is no defined specific method of determining whether to acquire a transmission opportunity. Supposing all terminals perform back-off as usual, there is a possibility that the terminal receiving strong interference power will won transmission opportunity enough, Ya contamination of interference to the neighboring cell signals, as described above , tends situation degradation in the receiving terminal of the received power by the transmission power suppression of the local cell signal occurs, the throughput of the whole in adjacent cells would be the communication quality deteriorates in its own cell system may be a factor to decrease.
[0040]
　For example, when a packet collision between the terminal occurs, each SINR of the base station by using the capture function: notify the terminal by calculating (Signal to Interference and Noise Ration SINR), high SINR value notified terminal is proposed for a wireless access control method to easily obtain a transmission opportunity by performing fixed backoff (e.g., see Patent Document 1). The aim of the link state is actively gives a transmission opportunity to a good terminal is the same as above. However, while it is necessary to base station notifies the SINR measurement result in the radio access control method, be performed SR transmission in the transmission time of the interference signal in the SR technique for the premise, such notification When performing packet switching that does not lead to improvement in throughput in SR transmission is a concern for.
[0041]
　Therefore, in this specification, proposed to improve the own cell and the entire system by performing the SR transmission while suppressing degradation of communication quality in the adjacent cell throughput, the following techniques (1) to (4) to.
[0042]
(1) terminal, before performing the SR transmission using the information available from the adjacent cell signal, by performing a new random backoff (SR backoff), to acquire the transmission opportunity while avoiding packet collisions .
[0043]
(2) above (1) terminal wishing to make an SR transmission according to the the information such as the distance (propagation loss) of up to strength and destination interference power itself is received, adjusting the SR backoff time the possibility to be. Specifically, by setting the weak terminal shorter latency interference power received, to facilitate acquires the transmission opportunity.
[0044]
(3) SR sent by that penalize terminal successfully packet transmission, a particular terminal allows to prevent monopolizing a transmission opportunity by SR transmission. Specifically, the terminal successfully packet transmitted by SR transmission, when setting a new backoff, a longer transmission wait time by providing additional back-off time.
[0045]
(4) In the case of employing at least one of techniques described above (2) or (3), the terminal allows the information to be used to adjust the SR backoff time, and notifies the base station. Specifically, the base station, based on such terminal number and throughput status of each terminal under its control parameters and to determine the backoff time in the SR transmission, determines an additional backoff time after SR transmission success transmitting a command signal to change the parameter to the terminal.
[0046]
　In this specification, base station and terminal, the back-off to be set in order to perform the SR transmission in a state in which observes the neighbor cell signal is referred to as "SR backoff", that the time for the SR backoff It is referred to as "SR back-off time". Incidentally, the normal packet transmission is not the SR transmission (i.e., when no observed adjacent cell signal, when transmitting a packet not based on information on the adjacent cell signal), the fact backoff performed in the prior art as the, in the following referred to as "conventional back-off", distinguished from the SR back off.
[0047]
　Generally, the number of slots decided randomly by multiplying a slot time of about several microseconds to determine the back-off time as the transmission waiting time. The number of slots is a value determined at random between the 0 CW (Contention Window) values. CW value, the initial value (reset value) and CWmin (the minimum value of CW), continue to increase until it reaches the CWmax (the maximum value of CW) every time fails to packet transmission, a successful packet transmission It is reset to CWmin. Further, when a terminal starts the transmission of a packet of another terminal during the transmission wait time, the terminal stops transmission waiting resumes transmission wait after the packet transmission of another terminal has been completed.
[0048]
　Additional CWmin, CWmax, such as a slot time, information used for adjusting the back-off time, or corresponds to a parameter for determining the backoff time. CWmin to set when SR transmission, CWmax, such as a slot time, information used to adjust the SR backoff time, or, to be understood to correspond to a parameter which determines the SR backoff time. As mentioned in addition, also the presence or absence as well as information about additional backoff time additional backoff, are intended to be included in the parameters that determine the SR backoff time.
[0049]
　In this specification, the above (1) and technology relating to (2) as in Example 1, a technique relating to (3) as Example 2 will be described technique as Example 3 relates to (4), in more detail . In Example 1, a terminal for performing SR transmission using the information available from the neighbor cell signal is the information such as the distance to the strength and the base station of the interference power itself is received (propagation loss) of the SR backoff time by adjusting to obtain a transmission opportunity while avoiding packet collision. In Example 2 and Example 3, the terminal or the base station is assumed to start the SR transmission after performing SR backoff. In Example 2, since the terminal has succeeded in SR transmission is set additional backoff time, equalization of transmission opportunities among the terminals is achieved. In Example 3, the base station, based on such terminal number and throughput status of each terminal under its control to set the parameters used in the SR backoff time adjustment for each terminal.
[0050]
　Incidentally, any embodiments described below, the reception power in the neighbor cell signal is assumed to be SR transmission when: OBSS-PD threshold, the technology disclosed herein is not limited to this not. The technology disclosed herein, for example, by using the information of the SR transmission or based on a SR parameters described in the neighbor cell signal packet (described above), the interference signal (not limited to adjacent cell signals) packet but also it includes the case of performing transmission.
Example 1
[0051]
　Figure 1 shows a configuration example of a wireless LAN system technology disclosed in this specification is applied. The illustrated system is connected to the plurality of base stations is established (AccessPoint: AP) and a plurality of terminals: consist (STATION STA), the periphery there are sources of interference such as adjacent cells and other systems.
[0052]
　AP1 constitutes the own cell (BSS) with STA1a and STA1b under. Similarly, AP2 constitute the own cell with STA2a subordinate, AP3 constitute the own cell with STA3a subordinate.
[0053]
　When referring to the arrangement of the cell and the terminal in FIG. 1, any cell of the cells and AP3 of AP2, become adjacent cells for the cells of the AP1, coverage overlap. However, cells of the cell and AP3 of AP2 shall not adjacent.
[0054]
　In the figure, arrows indicate the transmission direction of the packet. Previous solid arrow indicates the destination specified in the packet. Also, previous dotted arrows is not a destination of the packet indicates that the packet is coming. Accordingly, the adjacent cell signal arrives from the AP2 to STA1a under the AP1, the STA1b under the AP1 has been shown to reach an adjacent cell signal from AP3.
[0055]
　Although not shown by arrows in FIG. 1, the transmission signal to the AP1 from STA1a is also reaches near the AP2 and STA2a. Similarly, transmit signals to AP1 from STA1b can reach to near the AP3 and STA3a.
[0056]
　However, Example 1 Configuration of the applicable wireless LAN system technology relates is not limited to FIG. 1, the connection exists established a plurality of communication devices, as around the terminal to for each of the communication device it is sufficient that the communication device is present, regardless the positional relationship between if these conditions are met AP and STA.
[0057]
　2, in a wireless LAN system shown in FIG. 1, a functional configuration of the AP as well as the possible communication apparatus 200 that operates as a STA is schematically shown. Communication device 200 illustrated includes a communication unit 201, a control unit 202, a storage unit 203.
[0058]
　The communication unit 201 transmits and receives packets. Signal processing general data link layer and physical layer related to transmission and reception of data are to be understood as being implemented in the communication unit 201. For example, the communication unit 201 performs a measurement of the received power of the interference signals such as adjacent cell signal.
[0059]
　Control unit 202 performs settings of various parameters used by the communication unit 201. Further, when the communication device 200 operates as a STA in this embodiment, the control unit 202, in addition to controlling the execution of the normal packet transmission and a conventional back-off, execution of the decision and SR backoff existence of SR transmission also it controls.
[0060]
　Storage unit 203 stores the measurement results and various parameters used by the communication unit 201. If the communication device 200 operates as a STA in this embodiment, parameters used for SR transmission and SR backoff setting is also stored temporarily in the storage unit 203.
[0061]
　Also in Example 2 and Example 3 will be described later, like the communication device 200 shown in FIG. 2 is understood that it is possible to operate as an AP and STA.
[0062]
　Subsequently, as in Example 1, the terminal performs the SR backoff before performing SR transmission, also with information such as the distance to the strength and the destination of the interference power itself is received (propagation loss), SR-back It describes a method of adjusting the off-time. In the first embodiment, it is assumed that the assumed configuration of a wireless LAN system as shown in FIG.
[0063]
　FIG. 3 shows an exemplary communication sequence in the wireless LAN system shown in FIG. However, a respective horizontal axis indicates the time axis of the figure, each square represents a packet to be transmitted at a time corresponding to the position on the horizontal axis, the parallelogram indicates the transmission waiting time (backoff) . Also, previous solid arrow indicates a destination of the packet extending longitudinally from the packet. Moreover, previous dashed arrows extending longitudinally from the packet is not the destination of the packet indicates that the packet is coming. The communication sequence example shown in FIG. 3, each terminal is assumed to perform back-off of the prior art as, i.e. a conventional back-off.
[0064]
　In the figure, both the STA1a and STA1b, and set the conventional back-off, and what is waiting to be sent. At time T1, STA1a and STA1b in transmission wait, but receives a signal transmitted from the AP2, the information in the signal (BSS identifier described in the PHY header (PHY) (BSS Color), etc.) When identifying that a neighbor cell signal based, further its received power is aborts reception of the confirmation to the adjacent cell signal that is less OBSS-PD threshold to continue the conventional back-off in order to perform the SR transmission, respectively .
[0065]
　Incidentally, STA, which measured received power exceeds OBSS-PD threshold, SR transmission is not feasible. STA in this case, stop the conventional back-off is omitted resume conventional back-off from the end of the transmission of the neighboring cell signals, in FIG. 3 the illustration of such a STA.
[0066]
　When STA1a and STA1b performs a conventional back-off if both feasible SR transmission, in accordance with the remaining backoff time, AP2 and rather far from STA1b STA2a, won STA1a transmission opportunity closer AP2 and STA2a Resulting in. At time T2, STA1a conventional back-off earlier has been completed to start the SR transmission to the AP1. Accordingly, STA1b acknowledgment respect STA1a from AP1 (BA: Block Ack) until the packet is returned is a transmission inhibited state by setting the NAV (Network Allocation Vector).
[0067]
　However, so as to overlap the transmission period to STA2a from AP2, when STA1a is SR sends a packet to AP1, takes strong interference power from relative STA2a in receiving packets from AP2, the neighboring cells STA2a It would greatly degrade the reception quality.
[0068]
　Further, if each of STA1a and STA1b is performing an access procedure for adjusting the transmit power in accordance with the interference power, STA1a receive strong interference power from the AP2 have to SR transmission is lowered more transmit power become not, the reception quality of the AP1 is greatly deteriorates.
[0069]
　Therefore, when the STA1a and STA1b was observed adjacent cell signal from AP2 is located farther from an interference source AP2, or receive interference power weak STA1b is desirable to acquire a transmission opportunity, say be able to.
[0070]
　Thereafter, STA1a receives the BA packet from AP1 to end the packet transmission to AP1, if still transmit packets exist, it sets again conventional back-off (reset). Further, STA1b, when NAV is completed, resuming a conventional back-off. Then, at time T3, STA1a and STA1b in transmission wait, but receives a signal sent from the AP3, the neighboring cell signal based on information in the signal (such as BSS Color as described in the PHY header) Upon identifying that a further its received power is abort the reception of neighbor cell signals to confirm that less OBSS-PD threshold, respectively to continue the conventional back-off in order to perform the SR transmission.
[0071]
　Again, when STA1a and STA1b performs conventional back-off, in accordance with the remaining backoff time, rather than farther STA1a from AP3 and STA3a, STA1b close to AP3 and STA3a will won transmission opportunity. In particular, the illustrated example, while STA1b is resumed conventional back-off, because STA1a resets a conventional back-off with that performed the SR transmission immediately before, who STA1b is remaining backoff time short, it is expected that STA1b obtain a transmission opportunity to end the backoff first.
[0072]
　In time T4, both STA1b conventional backoff above is completed to start the SR transmission to AP1, STA1a is transmitted until the BA packet is returned with respect STA1b from AP1 sets the NAV prohibited state to become.
[0073]
　However, so as to overlap the transmission period to STA3a from AP3, the STA1b is SR sends a packet to AP1, takes strong interference power to STA3a in receiving packets from AP3, the reception of STA3a neighboring cells It would greatly degrade the quality. Further, since when each of STA1a and STA1b is performing an access procedure for adjusting the transmit power in accordance with the interference power, the STA1b receiving strong interference power from AP3 must be lowered more transmission power, AP1 of the reception quality is degraded significantly.
[0074]
　Therefore, when the STA1a and STA1b was observed adjacent cell signal from AP3 is located farther from an interference source AP3, or desirably low interference power received STA1a to acquire a transmission opportunity, and it is possible to say.
[0075]
　Figure 4 shows another exemplary communication sequence in the wireless LAN system shown in FIG. However, a respective horizontal axis indicates the time axis of the figure, each square represents a packet to be transmitted at a time corresponding to the position on the horizontal axis, the parallelogram indicates the transmission waiting time (backoff) (ibid.). Also, previous solid arrow indicates a destination of the packet extending longitudinally from the packet. Furthermore, dotted arrow head extending longitudinally from the packet is not the destination of the packet indicates that the packet has arrived (Id.).
[0076]
　The communication sequence example shown in FIG. 4, by applying the technology according to the first embodiment, each STA sets a new SR backoff when performing transmission waiting packets in the state that observes the neighbor cell signal together, and it adjusts the back-off time in the SR sent by information such as the distance (propagation loss) of the strength and AP of interference power itself observed. In Figure 4, which shows fill the parallelogram corresponding to the SR backoff by hatching.
[0077]
　In the figure, both the STA1a and STA1b, and set the conventional back-off, and what is waiting to be sent. At time T1, STA1a and STA1b in transmission wait, but receives a signal transmitted from the AP2, are adjacent cell signal based on information in the signal (such as BSS Color as described in the PHY header) When identifying that the further the received power aborts reception of the confirmation to the adjacent cell signal that is less OBSS-PD threshold, initiates a backoff for performing SR transmission, respectively.
[0078]
　Incidentally, STA, which measured received power exceeds OBSS-PD threshold, SR transmission is not feasible. STA in this case, stop the conventional back-off is omitted resume conventional back-off from the end of the transmission of the neighboring cell signals, in FIG. 4 the illustration of such a STA.
[0079]
　If STA1a and STA1b are both feasible for SR transmission is stopped a conventional back-off, newly set the SR backoff respectively, it waits for packet transmission. Each STA1a and STA1b, strength and interference power by itself to observe the distance between the AP is a packet transmission destination (transmission loss) in accordance with information such as, adjusting the SR backoff time. In the system configuration example assumed in FIG. 1 and FIG. 4, as compared with the interference power STA1a receives from AP2, weak interference power STA1b receives from AP2. Thus, while the direction of STA1b to set a shorter SR back-off time (referred to as "SR mode # 1"), STA1a becomes possible to set the long SR back-off time (referred to as "SR mode # 2") , STA1b is likely to acquire a transmission opportunity for the SR transmission than STA1a.
[0080]
　As a result, at the time T2, STA1b the SR back off earlier has been completed to obtain a transmission opportunity, to start the SR transmission to the AP1. Further, STA1a becomes transmission inhibited state during the set the NAV to BA packet is returned with respect STA1b from AP1.
[0081]
　Since located farther from such interference sources and is AP2, or receive interference power weak STA1b to acquire a transmission opportunity, STA1b to overlap the transmission period to STA2a from AP2 sends each packet also, it is possible to reduce deterioration of reception quality of STA2a neighboring cells.
[0082]
　Further, even when running an access procedure, each of STA1a and STA1b adjusts the transmit power according to the interference power, STA1b Since the observed weak interference power from AP2, lowering increase the transmission power of its own You need not be. Therefore, STA1b is possible to SR transmission without lowering the transmission power, AP1 can keep good reception quality.
[0083]
　Thereafter, STA1b receives BA packet from AP1 to end the packet transmission to AP1, if still transmit packets exist, it sets again conventional back-off (reset). Further, STA1a, when NAV is completed, resuming a conventional back-off. Then, at time T3, STA1a and STA1b in transmission wait, but receives a signal sent from the AP3, the neighboring cell signal based on information in the signal (such as BSS Color as described in the PHY header) Upon identifying that a further its received power is aborts reception confirmed to be less OBSS-PD threshold, it initiates a backoff for performing SR transmission, respectively.
[0084]
　Again, if STA1a and STA1b are both feasible for SR transmission is stopped a conventional back-off, newly set the SR backoff respectively, it waits for packet transmission. Each STA1a and STA1b, strength and interference power by itself to observe the distance between the AP is a packet transmission destination (transmission loss) in accordance with information such as, adjusting the SR backoff time. In this case, as compared with the interference power STA1b receives from AP3, since interference power STA1a receives from AP3 it is weak, while STA1a is to set a shorter SR backoff time (SR mode # 1), STA1b long SR backoff time will be (SR mode # 2) be set, in turn, is STA1a likely to acquire a transmission opportunity for the SR transmission than STA1b.
[0085]
　As a result, at the time T4, STA1a the SR back off earlier has been completed to obtain a transmission opportunity, to start the SR transmission to the AP1. Further, STA1b becomes transmission inhibited state during the set the NAV to BA packet is returned with respect STA1a from AP1.
[0086]
　Located farther from such an interference source to AP3, that is, undergoes interference power weak STA1a to acquire a transmission opportunity, STA1a to overlap the transmission period to STA3a from AP3 sends each packet also, it is possible to reduce deterioration of reception quality of STA3a neighboring cells.
[0087]
　Further, even when running an access procedure, each of STA1a and STA1b adjusts the transmit power according to the interference power, STA1a Since the observed weak interference power from AP3, lowering increase the transmission power of its own You need not be. Therefore, STA1a is possible to SR transmission without lowering the transmission power, AP1 can keep good reception quality.
[0088]
　In short, in the communication sequence example shown in FIG. 4, by adjusting the transmission wait time in response to interference power each terminal observes, without significantly affecting the reception quality of the entire system, and cause excess transmission suppression and so no, it is possible to perform the SR transmission. Specifically, the terminal wishing to make a SR transmission is stopped a conventional back-off, to add SR backoff is a random waiting time for SR transmission. The terminal, interference power itself observed, or, it is possible to adjust the SR backoff time according to the distance (propagation loss) of the AP is the destination.
[0089]
　5 shows, in Example 1, when the AP or STA receives a neighbor cell signal shows a processing procedure for setting the SR backoff in the form of a flowchart. Processing procedure illustrated, for example, a communication device 200 having the functional configuration shown in FIG. 2, when operating as an AP or STA in a wireless LAN system as shown in FIG. 1, the control unit 203 is a central to implement Te.
[0090]
　Communication device, for example, based on the BSS Color of simplified form described in the PHY header of the received signal packet, can identify the own cell signal and the adjacent cell signal. Incidentally, omitted if the own cell signal is identified the processing for the own cell signals is carried out, it is not shown process for 5 the own cell signal, also the description below.
[0091]
　Communication apparatus first obtains information on neighbor cell signal received (step S501), and determines whether the SR transmission is feasible (step S502).
[0092]
　For example, in step S501, as the information about the neighbor cell signal to obtain a received power of the neighboring cell signals. Then, in step S502, the received power is equal to or smaller than a predetermined detection threshold (OBSS-PD threshold), it is determined that SR transmission is feasible.
[0093]
　Alternatively, in step S501, it acquires information called SR parameter included in the neighbor cell signal packet. Then, in step S502, setting the transmission power so as not to affect the terminal belonging to the adjacent cell is possible, to determine an SR transmission is feasible.
[0094]
　Here, when the communication device is determined to be not feasible SR transmission (No in step S502), it stops the conventional back-off (step S506), and terminates the processing routine. In this case, when no longer observed adjacent cell signal, prior to resuming a backoff, starts transmitting a packet from the transmission waiting only the remaining backoff time.
[0095]
　On the other hand, (Yes in step S502) if the communication device is determined to be feasible for SR transmission, and interference power communication device itself observed, information on the distance to the other party to send a packet with the SR transmission (propagation depending on losses, etc.), it determines the SR mode (step S503).
[0096]
　In this embodiment, the influence of interference power from adjacent cells when performing the SR transmission, according to the combination of the communication distance to the SR transmission destination plurality of SR modes are defined. SR mode, for performing the SR transmission, impact as well as the corresponding relationship between the communication quality of the own cell to the communication quality of the neighbor cell as a source of interference. Each SR mode, to set the SR backoff time, CWmin, CWmax, and parameters associated with such slot time (described later), in other words, SR backoff time is set according to the SR mode. The communication quality of the influence is strong or the own cell to the neighboring cell should be set the parameters so that non SR mode longer SR backoff time good set, will be described later for details of the SR mode.
[0097]
　Then, the communication device, using the parameters for determining the SR backoff time associated with the SR mode selected, sets the SR backoff time (step S504).
[0098]
　The communication device, the SR backoff time set, the start of SR backoff for SR transmission (step S505), and terminates the processing routine. Then, unless the detection signals (frequency on the channel in use) to the media during the SR backoff, the communication device and acquires the transmission opportunity, performs packet transmission by SR transmission.
[0099]
　Figure 6 shows an example of a configuration of SR mode selection table. And the influence of interference power in performing SR transmission, a plurality of SR modes are defined according to the combination of the communication distance to the SR transmission partner. SR mode selection table shown in FIG. 6, by dividing the communication distance in the column direction with dividing the interference power in each row shows the SR mode corresponding to the combination of the communication distance and interference power. SR mode may also be referred to as an indicator and the influence of interference power at the time of SR transmission, the distance to the SR destination.
[0100]
　Communication device 200 operating as a STA or AP, for example stores the SR mode selection table in the storage unit 203. Therefore, the communication device 200 in step S503 in the flowchart shown in FIG. 5, by referring to the SR mode selection table, and interference power by itself to observe, in accordance with the communication distance to the AP, the appropriate SR mode can be set.
[0101]
　However, numerical values ​​shown in FIG. 6 is an example, not limited thereto. Further, although in FIG. 6 it is assumed that the STA holds the distance information between the AP, by replacing other indicators indicating whether STA and AP is how far the communication distance, SR mode selection it is also possible to configure the table. For example with a possible propagation loss and STA replaces the received signal, such as the communication distance of the beacon signal transmitted from the AP, it may be performed to select the SR mode.
[0102]
　Incidentally, SR mode selection table illustrated in FIG. 6 shows a list of SR mode that is defined corresponding to the combination of the communication distance to the interference power and the SR transmission partner, as a modified example, the interference power only defined and SR mode selection table listing the SR mode, it may also be mentioned SR mode selection table listing the SR mode defined only by the communication distance to the SR transmission partner by. Conversely, in addition to the communication distance and interference power even in the case where the parameters affecting the communication quality of the impacts, as well as the own cell of the communication quality of adjacent cells when performing the SR transmission is present, further also such parameters it is also possible to define the SR mode included.
[0103]
　In SR mode selection table shown in FIG. 6, the mode number according to the strength or the communication distance of the interference power is allocated to the uplink order. Should set the parameters as long SR backoff time as SR mode communication quality influences strongly or own cell to the neighboring cell is not good is set. Therefore, set the short SR backoff time mode number for small SR mode, it should provide a long SR backoff time for SR mode mode number is large.
[0104]
　Figure 7 shows a configuration example of a parameter setting table for each SR mode. Parameter setting table is a simplified chart showing the parameters for setting the SR backoff time for each SR mode. Parameters, and default parameters consisting of a fixed value, the count parameter count to the value is sequentially updated.
[0105]
　Communication device 200 operating as the STA, SR backoff time contention window for each SR mode the minimum value (CW) (hereinafter referred to as "SR_CWmin") and a maximum value (hereinafter referred to as "SR_CWmax" " and a slot time (slot time), stored in the storage unit 203 as the default parameter in the parameter setting table for each SR mode.
[0106]
　Communication device 200 in step S504 in the flowchart shown in FIG. 5, from the parameter setting table stored in the storage unit 203, SR_CWmin corresponding to SR mode set in step S503, SR_CWmax, as well as each of the slot time read the parameter values, it can be set (and interference power itself observed, corresponding to the combination of the communication distance to the AP), SR backoff time. Basically, SR_CWmin continue to increase the SR_CW value until it reaches the SR_CWmax every time fails SR transmission as an initial value, by multiplying a slot time random value determined between 0 and SR_CW value, SR it is assumed that the back-off time is obtained.
[0107]
　As shown in FIG. 7, SR mode # 1 → # 2 → in order of ♯3 By setting a high value of SR_CWmin, compared to SR backoff time of STA you select SR mode # 1, the SR mode # 3 It is set to be able to lengthen the SR back-off time of the selected STA. That is, from the viewpoint that it is necessary to lengthen the strong interference power as STA having received the SR backoff time, set the short SR backoff time mode number for small SR mode, the mode number is large SR mode it is for it is possible to set a long SR back-off time.
[0108]
　Further, as shown in FIG. 7, the communication device 200 is further provided with a region for storing the count parameters, such as number of failed packet transmission in each SR mode, it counts the transmission number of failed packet per SR mode management It has become way. However, SR modes # 0 in FIG. 7, without additional SR backoff, by conventional back-off only a mode that allows to perform SR transmission. As mentioned in addition, the communication device 200, a transmission failure count when the transmitted packet (by conventional back-off) in a state that does not observe the neighbor cell signal is divided and (SR mode every) transmission failure times when the SR transmission It has also become to count and to supervises as. From the viewpoint of the range for obtaining a random value used in the calculation of the back-off time expanding according to a transmission failure count is included in the count parameter also determines the SR backoff time parameter.
[0109]
　Incidentally, SR_CWmin, the value of each default parameters SR_CWmax and Slot Time is not limited to the values ​​specified in Figure 7, may be set to different values ​​for each SR mode. In addition to the default parameters and count parameters shown in FIG. 7, if any parameter capable of adjusting the transmission waiting time SR backoff may be set for each SR mode.
[0110]
　8, in the first embodiment and illustrates a processing procedure by the communication device carried out after completion of packet transmission in the form of a flowchart. For example, the communication device 200 having the functional configuration shown in FIG. 2, when operating as a STA in a wireless LAN system as shown in FIG. 1, the control unit 203 is at the heart to carry out this procedure.
[0111]
　The STA, upon completion of the packet transmission (step S801), checks whether conducted SR transmission (step S802).
[0112]
　STA is not the SR transmission, if it has performed the transmission normal packet (No in step S802), the further checks whether successful packet transmission (Step S808). Whether successful packet transmission may be determined by whether the STA is returned acknowledgment (BA) packet from the destination AP.
[0113]
　If the transmission normal packet is successful (Yes in step S808), STA resets the transmission number of failures during transmission normal packet to 0 (step S809). Further, if the transmission normal packet has failed (No in step S808), STA increments the transmission number of failures during transmission normal packet by one (step S810).
[0114]
　On the other hand, (Yes in step S802) is when the STA had conducted an SR transmission, manages the transmission failure count for each SR mode. Specifically, STA further checks whether successful SR transmission (step S803). Whether successful SR transmission may be determined by whether the STA is returned acknowledgment (BA) packet from the destination AP.
[0115]
　If successful SR transmission (Yes in step S803), STA resets the transmission number of failed SR mode at that time to 0 (step S804). Further, in the case of failure to the SR transmission (No in step S803), STA increments the transmit failure count at that time SR mode by one (step S807).
[0116]
　Then, STA sets a backoff time (step S805). In the case of a conventional back-off, decide CW value according to transmission failure count, (the normal transmission) random value between 0 and CW value by multiplying a slot time to determine the back-off time. CW value, the CWmin as an initial value, increases to CWmax according to transmission failure count. Also, a successful transmission normal packet (Yes in step S808), since the transmission failure count is reset to 0 (step S809), resets the result CW value to CWmin.
[0117]
　In the case of SR backoff at step S805, the decide SR_CW value according to transmission failure count for each SR mode, (when SR transmission) random value between 0 and SR_CW value multiplied by the slot time to obtain the SR back-off time. SR_CW value, the SR_CWmin as an initial value, increases until SR_CWmax according to transmission failure count. Also, a successful packet transmission by SR transmission (Yes in step S803), since the transmission failure count which counts every SR mode is reset to 0 (step S804), resets the result SR_CW value to SR_CWmin . Processing in step S805 corresponds to the processing performed in the step S504 in the flow chart shown in FIG.
[0118]
　When the transmission data is generated, wait AIFS (Arbitarian Inter Frame Space) is, STA initiates a backoff at the backoff time set in step S805 or SR backoff time (step S806).

claims

A communication unit for transmitting a packet based on information about interference signal,
　the interference power or based on at least one of information related to the communication distance to the destination of the packet, transmission in a state that observing the interference signal waiting a control unit for controlling the time
communication apparatus comprising.
[Requested item 2]
　Wherein the control unit, the interference power or in response to said at least one of information regarding the communication distance, selecting parameters for determining a transmission waiting time in a state that observe interference signal,
the communication apparatus according to claim 1.
[Requested item 3]
　Wherein, as the interference power is high, or, as the communication distance is long, sets the longer transmission wait time, as the interference power is low, or, the higher the communication distance is short, the shorter transmission wait set,
the communication apparatus according to claim 1.
[Requested item 4]
　The control unit manages in association with the modes defined on the basis of the transmission frequency of failures when transmitting a packet, in at least one of information relating to the interference power or the communication distance based on the information about the interference signal,
wherein the communication apparatus according to claim 1.
[Requested item 5]
　Wherein the control unit is managed separately and a second transmission failure count when the transmitted packets based on information about the first transmission failure count the interference signal when the transmitted packets while no observe interference signals ,
the communication apparatus according to claim 1.
[Requested item 6]
　The information associated with the communication distance includes information related to the propagation loss of the transmission destination,
the communication device according to claim 1.
[Requested item 7]
　A communication step of transmitting the packet based on the information about the interference signal,
　the interference power or based on at least one of information related to the distance to the destination of the packet, transmission waiting time in a state that observing the interference signal a control step of controlling the
communication method with.
[Requested item 8]
　A communication unit for transmitting a packet,
　and a control unit for controlling the transmission latency in transmitting a packet,
comprising a,
　wherein, the first transmission when transmitting a packet with no observed interference signal latency, sets the transmission wait time plus additional latency,
communication device.
[Requested item 9]
　Wherein, in response to the result of sending a packet based on information about interference signal, setting a transmission wait time plus the additional latency to the first transmission waiting time,
the communication of claim 8 apparatus.
[Requested item 10]
　Wherein the control unit sets an additional waiting time based on information about interference signal,
the communication apparatus according to claim 8.
[Requested item 11]
　A communication step of transmitting a packet,
　and a control step for controlling the transmission latency in transmitting the packet
has,
　in the control step, a first transmission when transmitting a packet in a state that does not observe interference signals latency, sets the transmission wait time plus additional latency,
communication method.
[Requested item 12]
　A control unit for controlling the transmission latency in state based on information about interference signals are observed interference signal of the communication partner can be a packet transmission,
　and notifies the information for determining the transmission waiting time to the communication partner a notification unit,
a communication device having a.
[Requested item 13]
　Operates as an access point,
　wherein the notification unit to the terminal under the possible transmission of a packet based on the information about the interference signal, and notifies the information for determining the transmission waiting time,
according to claim 12 Communication device.
[Requested item 14]
　Wherein information for determining the transmission waiting time includes parameters for determining a transmission waiting time in a state that observe interference signal,
the communication apparatus according to claim 13.
[Requested item 15]
　Wherein information for determining the transmission waiting time includes information specifying the presence or absence of additional latency for the transmission latency in transmitting the packet with no observed interference signal,
the communication apparatus according to claim 13.
[Requested item 16]
　Wherein information for determining the transmission waiting time further comprises information about the value of the additional waiting time,
the communication apparatus according to claim 15.
[Requested item 17]
　The notification section in association with the modes defined based on at least one of information about the interference power or communication distance, and notifies the information for determining the transmission waiting time,
the communication apparatus according to claim 13.
[Requested item 18]
　The notification unit, the control unit based on information regarding at least one of said terminal number or throughput of the terminal under is set, and notifies the information for determining the transmission waiting time,
to claim 13 the communication apparatus according.
[Requested item 19]
　A control step for controlling the transmission wait time in a state that observe interference signal of the communication partner can be a packet transmission based on the information about the interference signal,
　and notifies the information for determining the transmission waiting time to the communication partner and notifying step,
the communication method comprising the.
[Requested item 20]
　A communication unit for transmitting and receiving a packet,
　and a control unit for controlling the transmission latency in transmitting the packet
comprises a,
　the control unit on the basis of the information described in the frame of the communication unit has received, It sets the transmission wait time in a state that observe interference signal,
the communication device.