JP2008283677A - Radio access system, and radio terminal station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing scheme for sleep-frame information for efficient power saving at a radio terminal station. <P>SOLUTION: In a sleep operation processing unit 103 of a radio mobile terminal MT, when a first reception data determination section 111 determines presence of broadcast band allocation, reception of broadcast data is reserved. Furthermore, when a second reception data determination section 112 determines presence of band allocation to a present station excepting for broadcast, transmission/reception of data is reserved, sleep cancellation is then performed, and reserved data transmission/reception is performed. In the case where the second reception data determination section determines absence of band allocation, however, reserved data transmission/reception is performed and a sleep state is recovered. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radio access system including a radio base station and a radio mobile terminal station that transmits / receives information to / from the radio base station, and particularly relates to sleep frame information for battery saving in the radio terminal station. It relates to the processing method.

  At present, device terminals such as personal computers are widespread, LANs are established in companies, etc., data exchange between personal computers, shared use of devices such as printers, and access to external networks are performed.

  In networking such as LAN, connections between servers, personal computers and other devices are wired. Rewiring must be done each time the layout is changed, such as moving the PC layout. The same is true for highly portable notebook computers. When connected to an existing LAN, it can only be used where there is a wiring connection.

  As a wireless connection to a network or the like, a method using a mobile phone or PHS is widely used. Thereby, if it is in the area of the said wireless network, it is possible to access the network even while moving. The transmission capacity of the mobile phone and PHS by wireless connection is currently a maximum of 64 [kbps]. For this reason, it can be used comfortably when sending and receiving Internet mail and accessing websites with relatively little data capacity, but it can be used for large-capacity data such as moving images that are expected to be used as content in the future. It is hard to say that it is suitable for access. For this reason, a wireless access system capable of accessing a larger amount of data has been demanded and has been studied in IEEE802.11 (US), ATM Forum (US), ETSI-BRAN (Europe), MMAC (Japan), etc. Yes.

  Looking at the wireless access systems being considered by MMAC, using the frequency bands of 5 [GHz] and 25 [GHz], outdoors 20 [Mbps] or more (1 user maximum 10 [Mbps]), indoor 156 [Mbps] The target is information transmission speed. Among these, in the 5 [GHz] band, the OFDM scheme is used as the radio scheme, and the transmission speed of 20 [Mbps] or more is targeted. Hereinafter, the 5 [GHz] band of MMAC will be described.

  Data transmission / reception between the wireless base station (hereinafter referred to as AP) and the wireless mobile terminal station (hereinafter referred to as MT) is performed in units of 2 [ms] MAC (Media Access Control) frames. One MAC frame is composed of six physical channels (BCH, FCH, ACH, SCH, LCH, and RCH). BCH is a channel having information such as an ID of an AP to which a MAC frame belongs. The FCH is a channel describing the structure of a MAC frame that continues after the FCH. ACH is a channel describing ACK information for RCH. The SCH is a channel for data transmission other than BCH, FCH, ACH, and RCH, and is a short size channel. LCH is a channel for data transmission other than BCH, FCH, ACH, and RCH, and is a channel for a long size. RCH is a channel for random access. 1 MAC frame is data transmission from BCH, FCH, ACH, AP to MT, Down-Link composed of SCH and LCH, data transmission from MT to AP, and composed of SCH and LCH It consists of Up-Link and RCH (Fig. 2). Bandwidth allocation in data transmission / reception between the AP and each MT is described in the FCH, and each MT transmits / receives data based on the FCH.

  A transmission / reception operation in the AP and MT will be described with reference to FIGS. When data that needs to be transmitted is received from the Ethernet network 8, the CL unit (convergence layer data conversion unit) 5 performs data format conversion and stores the data in the transmission buffer 1. In the DLC unit (data link control unit) 2, a sequence number is added for selective retransmission processing (Selective Repeat ARQ), and the encoding process according to the encoding mode described in the scheduling data buffer unit 9 is performed. And transmit via the RF unit 7 and the antenna unit 4. The received PHY unit 12 performs decoding processing according to the encoding mode described in the scheduling data buffer unit 9 on the received encoded data via the antenna unit 4 and the RF unit 7, and an error occurs in the reception DLC unit 10. No data is stored in the reception buffer unit 13, and a transmission request for ACK / NAK information is sent to the MAC unit (media access control unit) 15. The data stored in the reception buffer unit 13 is format-converted by the CL unit 5 and sent to the Ethernet network 8.

  In MT202, a bandwidth allocation request for data transmission from MT202 is sent to AP201. In the AP 201, a bandwidth required for data transmission from the own AP 201 to each MT and a bandwidth allocation request from each MT are allocated by the scheduling unit 14 in the scheduling unit 14, and based on the schedule by the scheduling unit 14 Information is described in the scheduling data buffer unit 9 and sent to the MT using the FCH. The MT 202 describes information related to the own MT in the scheduling data buffer unit 9 among the scheduling information described in the received FCH. AP and MT perform transmission / reception timings in transmission / reception and encoding modes in the PHY units 3 and 12 based on scheduling information described in the scheduling data buffer unit 9.

  Since a wireless mobile terminal station (MT) is a mobile terminal, it is required to reduce the size and weight of the device and increase the usage time. Usually, when accessing a network such as Ethernet from a personal computer, data does not always flow, but a huge amount of data flows locally when accessed. For this reason, the access time to the network is shorter than the usage time of the personal computer. For this reason, reducing the power consumption of the MT in a state where the network access is not being performed (hereinafter referred to as a standby state) leads to a longer MT usage time.

  Normally, the necessary circuit voltage is supplied during communication between the MT and the AP. On the other hand, during the process of reducing power consumption in the standby state (hereinafter referred to as battery saving), the power supply to unnecessary circuits is stopped (sleep state), and access from APs is performed at intervals determined between APs. Supply voltage only when checking whether there is a request (sleep release check processing). Thereby, power consumption in the standby state is reduced.

  Information processing in battery saving will be described with reference to FIG. When the standby state continues and it is determined to shift to the sleep state, the MAC unit 6 sends the sleep request and the requested number of sleep frames to the AP via the transmission PHY unit 3. When the sleep permission signal including the number of permitted sleep frames and the number of frames for synchronization adjustment is received from the AP, the MAC unit sets the number of frames for synchronization adjustment + 1 in the sleep timer unit 106 and temporarily enters the sleep state. . The sleep timer unit 106 sends a processing request to the sleep operation processing unit 103 after the set number of frames. The sleep operation processing unit 103 starts sleep release check processing, and sets reception of BCH from the MAC unit 6 in the transmission / reception schedule data buffer unit 9. When the frame head is detected, the signal received by the RF unit 7 is decoded by the reception PHY unit 12, and when the received signal is BCH, the BCH is sent to the BCH reception buffer unit 102. In the FCH reception determination unit 101, the presence / absence flag for bandwidth allocation to the sleeping MT described in the BCH of the BCH reception buffer unit 102 is confirmed. Send to part 6. The MAC unit 6 sets reception of the FCH in the transmission / reception schedule data buffer unit 9. When the FCH is received, the received FCH is sent to the FCH reception buffer unit 105, and the reception data determination unit 104 determines the presence / absence of bandwidth allocation related to the own MT. The reception data determination unit 104 sends a determination result to the sleep operation processing unit 103, and the sleep operation processing unit 103 sends a sleep release request to the MAC unit 6 to release the sleep. When the reception data determination unit 104 determines that there is no allocation, or when the FCH reception determination unit 101 determines that there is no allocation, the MAC unit 6 continues the sleep process and sends the allowed sleep to the sleep timer unit 107. Set the number of frames and enter sleep mode. When the sleep is canceled from the MT, that is, when there is information to be transmitted from the MT to the AP, the MAC unit 6 cancels the sleep and sends a bandwidth allocation request for information transmission to the AP using the RCH. Receiving the bandwidth allocation request, the MT is released from sleep.

  FIG. 6 shows the flow of information processing until the sleep state is entered. The MT in the standby state raises a sleep request to the AP (S101). At this time, the number of sleep frames requested from the MT is increased at the same time. The requested number of sleep frames is compared with the transmission frame period of broadcast data transmitted from the AP to all MTs, and the number of sleep frames permitted for the MT requesting the sleep is calculated (S102). Further, in order to be able to receive broadcast data transmitted from the AP by the MT, the number of frames for synchronization adjustment is calculated so that the sleep release chucking process is synchronized with the broadcast frame period (S103). The AP sends the number of permitted sleep frames and the number of frames for synchronization adjustment to the MT (S104). The MT temporarily enters a sleep state for the number of frames for synchronization adjustment, and performs a sleep release check process for the next frame (S106). Here, when there is no bandwidth allocation related to the own MT, the sleep state is entered until the sleep release check process after the number of permitted sleep frames (S106 to S108). In the sleep release check process, when there is a bandwidth allocation related to the own MT, the MT releases the sleep and returns to the normal operation.

  Further, FIG. 7 shows a flow from sleep state to sleep release. In the case of the sleep release check frame, the MT checks a flag indicating whether or not there is bandwidth allocation for the MT during sleep described in the BCH at the beginning of the MAC frame (S201 to S203). If the flag is on (with bandwidth allocation), then the FCH following the BCH on the MAC frame is decoded, and it is determined whether there is bandwidth allocation related to the own MT. When the FCH has a broadcast bandwidth allocation (S206), the MT receives broadcast data from the Down-Link following the FCH (S211). If there is other bandwidth allocation to be transmitted / received by the own MT (S207), transmission / reception processing is performed according to this (S211). When there is a bandwidth allocation related to the own MT, the MT cancels the sleep. On the other hand, if the flag in the BCH is OFF (no band allocation), or if there is no band allocation related to the own MT in the FCH, the MT returns to the sleep state (S204). As a result, it is possible to reduce wasteful power consumption in the standby state, and as a result, increase the usage time.

  In the battery saving, when there is a broadcast data reception request, the sleep is released. Thereby, even when broadcast data is transmitted from the AP and the AP temporarily shortens the broadcast frame period, the MT can easily follow and receive.

  However, after the broadcast data reception is completed, the MT in the standby state continues to supply power until the time until the transition to the sleep determination and the completion of the sleep state. In addition, even when the broadcast data from the AP fits into one MAC frame, the MT similarly cancels the sleep state in the same manner, so that it consumes power for the time until it enters the sleep state again. It is out.

  This will be described with reference to FIG. In FIG. 8, the frame and time are shown from the top, the schematic configuration of the frame, the signal direction between AP and MT, and the power supply / stop of the MT. Each frame number is expressed as f, f + 1, f + 2. Ta and tb represent time.

  The frame f + 1 is the sleep release check frame, and the frame f + 1 shows the supply / stop state of the power consumption of the MT during sleep when the AP sends out broadcast data and there is no other bandwidth allocation to the MT. .

  In order to check sleep release for frame f + 1, the MT during sleep supplies power at time ta to prepare for BCH reception of frame f + 1. BCH from AP is received ([1]), and a flag indicating the presence / absence of bandwidth allocation is checked in the BCH for the sleeping MT. If the flag is on (band allocation), the next FCH is Receive ([2]). Broadcast data is received according to the broadcast bandwidth allocation information described in the FCH ([3]). After the reception is completed, the MT cancels the sleep, sends a sleep request to the AP at frame f + 4 ([10]), obtains a sleep permission from the AP at frame f + 5 ([13]), and at time tb The MT again stops supplying power and returns to the sleep state.

  As described above, until the sleep permission from the frame f + 2 to the frame f + 5 is obtained, the MT continues to be activated in a state where there is no transmission / reception data, and thus wasteful power consumption is caused.

  An object of the present invention is to provide a sleep frame information processing method for reducing the above-mentioned wasteful power consumption.

In order to achieve the above object, the present invention provides a radio access system comprising a radio base station and a plurality of radio terminal stations that transmit and receive information to and from the radio base station, wherein the radio terminal station is in a standby state. A sleep processing unit for controlling power supply to be stopped and releasing the power supply stop state at a predetermined timing, and the sleep processing unit is configured to release the power supply stop state; When determining whether there is bandwidth allocation of broadcast data transmitted from the wireless base station, and determining that there is broadcast bandwidth allocation, after receiving the broadcast data based on the allocation, The gist is to control the power supply to stop.
In the present invention, the sleep processing unit determines whether or not there is data bandwidth allocation to its own wireless terminal station in addition to the broadcast reception data, and as a result of the determination, determines that there is only the broadcast bandwidth allocation. In this case, the power supply is controlled to be stopped immediately after receiving the broadcast data based on the assignment.
The present invention relates to a sleep process for controlling to stop power supply in a standby state and to cancel the power supply stop state at a predetermined timing in a wireless terminal station that transmits and receives information wirelessly with a wireless base station The sleep processing unit determines whether or not there is a bandwidth allocation of broadcast data transmitted from the radio base station when the power supply stop state is released, and there is a broadcast bandwidth allocation. If it is determined that the broadcast data is received based on the assignment, the power supply is controlled to be stopped.

  With this configuration, when only the broadcast data is assigned at the time of sleep release check, the MT can receive the broadcast data while continuing the sleep state.

  In the radio access system of the present invention, when the radio base station changes the broadcast frame period, the radio base station transmits only the changed broadcast frame period, and the sleep processing unit of the radio terminal station stores the requested sleep frame information A request sleep frame information storage unit, and a sleep frame calculation unit that calculates sleep frame information from the changed broadcast frame period and the request sleep frame information stored in the request sleep frame information storage unit. It may be configured. With this configuration, when the broadcast frame period is changed, the AP sends the changed frame period to the MT as broadcast control information, and the AP and each MT change the requested sleep frame and broadcast frame period of each MT. By calculating the number of subsequent sleep frames, it is possible to update the number of sleep frames while each MT continues in the sleep state.

  As described above, according to the configuration of the present invention, it is possible to continuously receive broadcast data without canceling the sleep state. It becomes possible to prevent power consumption.

  By using the wireless access system of the present invention, it is possible to receive broadcast data in the sleep state without canceling sleep, and reduce unnecessary power consumption required until re-sleep when the sleep is canceled. It becomes possible.

  Also, even when the broadcast data transmitted from the AP locally increases and the broadcast frame period is changed, it is possible to continuously receive the broadcast data without canceling the sleep similarly.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings. In addition, the same code | symbol is used for the location which shows the structure same as FIG.

  FIG. 1 is a basic configuration diagram relating to a sleep processing unit of a wireless terminal station according to an embodiment of the present invention. When the MT determines that the state shifts to the sleep state, the MAC unit 6 sends the sleep request and the number of requested sleep frames to the AP via the transmission PHY unit 3. When the MT receives a sleep permission signal including the number of permitted sleep frames and the number of frames for synchronization adjustment from the MT, the MAC unit 6 sets the number of frames for synchronization adjustment + 1 in the sleep timer unit 106, and then once sleeps. Enter the state. The sleep timer unit 106 sends a processing request to the sleep operation processing unit 103 after the set number of frames. The sleep operation processing unit 103 starts sleep release check processing, and sets reception of BCH from the MAC unit 6 in the transmission / reception schedule data buffer unit 9. When the frame head is detected, the signal received by the RF unit 7 is decoded by the reception PHY unit 12, and when the received signal is BCH, the BCH is sent to the BCH reception buffer unit 102. The FCH reception determination unit 101 checks the bandwidth allocation presence / absence flag for the sleeping MT described in the BCH of the BCH reception buffer unit 102. If the previous period flag is on (allocation), the FCH reception request is sent to the MAC Send to part 6. The MAC unit 6 sets reception of the FCH in the transmission / reception schedule data buffer unit 9. When the FCH is received, the received FCH is sent to the FCH reception buffer unit 105, and the reception data determination unit 113 determines whether or not there is bandwidth allocation related to its own MT. A transmission / reception schedule corresponding to the bandwidth allocation is set in the transmission / reception schedule data buffer unit 9. The reception data determination unit 113 includes a first reception data determination unit 111 that determines the presence / absence of bandwidth allocation for broadcast information, and a second reception that determines the presence / absence of bandwidth allocation for information related to the self-MT other than broadcast. The determination of whether or not there is bandwidth allocation in the second received data determination unit 112 is sent to the sleep operation processing unit 103. When the second received data determination unit 112 determines that there is band allocation, the sleep synchronization processing unit 103 sends a sleep release request to the MAC unit 6 and ends the sleep operation. On the other hand, when there is no bandwidth allocation, the sleep operation processing unit 103 sees the end of the schedule set in the transmission / reception schedule data buffer unit 9 and returns to the sleep state. At this time, the number of allowed sleep frames is set in the sleep timer unit 106.

  When receiving information related to a change in the broadcast frame period by broadcast, the sleep operation processing unit 103 sends the change information to the sleep frame calculation unit 114. The sleep frame calculation unit 114 calculates sleep frame information from the update information and the request sleep frame information of the own MT stored in the request sleep frame information storage unit 115, and the sleep frame calculation unit 114 calculates the sleep frame information as new sleep frame information. Set in timer section 106. This eliminates the need to send sleep frame information to individual MTs in the sleep state when changing the broadcast frame period. At the same time, each MT can change the number of sleep frames without releasing sleep.

  In this case, that is, when the AP changes the broadcast frame period, it is only necessary to transmit the changed broadcast frame period. The MT processes this as the change information.

  FIG. 9 is a flowchart for explaining the operation in the sleep unit according to the embodiment of the present invention. In the case of a sleep release check frame, the MT checks a flag indicating whether or not there is bandwidth allocation to the sleeping MT in the BCH at the beginning of the MAC frame (S301 to S303). If the flag is on (with bandwidth allocation), then the FCH following the BCH on the MAC frame is decoded to determine whether there is broadcast bandwidth allocation. If there is bandwidth allocation, reception of broadcast data following the FCH is received. Is reserved (S307 to S308). Similarly, it is determined whether or not there is a bandwidth allocation related to the own MT except for the broadcast, and if there is a bandwidth allocation, a transmission / reception reservation is made in the same manner (S309 to S310). When there is a bandwidth allocation related to the own MT excluding the broadcast, the sleep release operation is performed to transmit / receive the data reserved for reception (S311 to S312). When there is no bandwidth allocation, the data of the reception reserved Transmission / reception is performed to return to the sleep state (S304 to S306).

  FIG. 10 is a diagram illustrating the supply / stop state of MT power consumption in the sleep unit according to an embodiment of the present invention. In FIG. 10, the frame and time from the top, the schematic configuration of the frame, the signal direction between AP and MT, and the power supply / stop of MT are shown, and the top frame shows a frame delimiter by a vertical line. Each frame number is expressed as f, f + 1, f + 2. Ta and tb represent time.

  The frame f + 1 is the sleep release check frame, and the frame f + 1 shows the supply / stop state of the power consumption of the MT during sleep when the AP sends out broadcast data and there is no other bandwidth allocation to the MT. .

  In order to check sleep release for frame f + 1, the MT during sleep supplies power at time ta to prepare for BCH reception of frame f + 1. BCH from AP is received ([1]), and a flag indicating the presence / absence of bandwidth allocation is checked in the BCH for the sleeping MT. If the flag is on (band allocation), the next FCH is Receive ([2]). Broadcast data is received according to the broadcast bandwidth allocation information described in the FCH ([3]). After completion of reception, the MT again stops supplying power at time tb and returns to the sleep state.

  As described above, when there is only a broadcast bandwidth allocation when the sleep cancellation check is performed, the MT during sleep consumes unnecessary power because it immediately returns to the sleep state after receiving data according to the allocation. As a result, it is possible to extend the usage time.

The basic block diagram regarding the sleep processing part of MT which is one Example of this invention. MMAC frame structure diagram. 1 is a schematic diagram of a configuration of a radio base station (AP). 1 is a schematic diagram of a configuration of a wireless mobile terminal station (MT). The basic block diagram of the conventional sleep processing part. The flowchart explaining the operation | movement in the conventional sleep part. The flowchart explaining the operation | movement in the conventional sleep part. The figure explaining the supply / stop state of MT consumption voltage in the conventional sleep part. The flowchart explaining the operation | movement in the sleep part which is one Example of this invention. The figure explaining the supply / stop state of MT power consumption in the sleep part which is one Example of this invention.

Explanation of symbols

1: Transmission buffer unit 2: Transmission DLC unit 3: Transmission PHY unit 4: Antenna 5: CL unit 6: MAC unit 7: RF unit 8: Ethernet 9: Transmission / reception schedule data buffer unit 10: Reception DLC unit 11: Sleep processing unit 12: reception PHY unit 13: reception buffer unit 14: scheduling unit 15: MAC unit 101: FCH reception determination unit 102: BCH reception buffer unit 103: sleep operation processing unit 104: reception data determination unit 105: FCH reception buffer unit 106: Sleep timer unit 111: first received data determination unit 112: second received data determination unit 113: received data determination unit 114: sleep frame calculation unit 115: requested sleep frame information storage unit 201: AP
202: MT

Claims (4)

In a wireless access system comprising a wireless base station and a plurality of wireless terminal stations that transmit and receive information wirelessly with the wireless base station,
The wireless terminal station has a sleep processing unit that controls to stop power supply in a standby state and to release the power supply stop state at a predetermined timing,
The sleep processing unit
When the power supply stop state is released, it is determined whether or not there is a bandwidth allocation of broadcast data transmitted from the radio base station. If it is determined that there is a broadcast bandwidth allocation, Control to stop the power supply after receiving the broadcast data.
A wireless access system characterized by that. The sleep processing unit
In addition to the broadcast reception data, the presence / absence of data bandwidth allocation to its own wireless terminal station is determined, and if it is determined that there is only the broadcast bandwidth allocation, the broadcast is allocated based on the allocation. After receiving the data, control to stop the power supply immediately,
The wireless access system according to claim 1. When changing the broadcast frame period, the radio base station transmits only the changed broadcast frame period,
The sleep processing unit of the wireless terminal station includes a request sleep frame information storage unit that stores request sleep frame information, a broadcast frame period after the change, and request sleep frame information stored in the request sleep frame information storage unit. The wireless access system according to claim 1, further comprising a sleep frame calculation unit that calculates sleep frame information from the sleep frame information. In a wireless terminal station that transmits and receives information wirelessly with a wireless base station,
Having a sleep processing unit that controls power supply to be stopped in a standby state and to release the power supply stop state at a predetermined timing;
The sleep processing unit
When the power supply stop state is released, it is determined whether or not there is a bandwidth allocation of broadcast data transmitted from the radio base station. If it is determined that there is a broadcast bandwidth allocation, Control to stop the power supply after receiving the broadcast data.
A wireless terminal station.

Images