JP4896289B2 - Wireless terminal station - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio access system including a radio base station and a radio terminal station that transmits / receives information to / from the radio base station, and particularly relates to an improvement of a sleep processing unit for battery saving in the radio terminal station.
[0002]
[Prior art]
At present, device terminals such as personal computers are widespread, LANs are established in companies and the like, data exchange between personal computers, shared use of devices such as printers, and access to external networks are performed.
[0003]
In networking such as a LAN, a connection between a server, a personal computer, and other devices is a wired connection. For this reason, rewiring must be performed each time the layout is changed, such as moving the personal computer layout. The same applies to a notebook PC with high mobility, and when it is connected to an existing LAN, it can be used only in a place with a wiring connection port.
[0004]
As a wireless connection to a network or the like, a method using a mobile phone or PHS has been widespread. As a result, the network can be accessed even while moving within the area of the wireless network.
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.
[0005]
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.
[0006]
Looking at the wireless access systems being considered in 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 method is used as a wireless method, and a transmission speed of 20 [Mbps] or more is targeted. Hereinafter, the 5 [GHz] band of MMAC will be described.
[0007]
Data transmission / reception between the wireless base station (hereinafter referred to as AP) and the wireless 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, RCH), where BCH is a channel having information such as the ID of the AP to which the MAC frame belongs, and FCH is a MAC that continues after FCH. A channel describing the structure of the frame, ACH is a channel describing ACK information for RCH, SCH is a channel for data transmission other than BCH, FCH, ACH, and RCH, and is a channel for a short size. , LCH are channels for data transmission other than BCH, FCH, ACH, and RCH, and are channels for long sizes, and RCH is a channel for random access. One 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 performs data transmission / reception based on the FCH.
[0008]
When BCH is transmitted, it is transmitted in a form in which three signals of preamble A field, B field, and C field, which are known signals, are added to the head of BCH (FIG. 3). Signals in the order of preamble A field and B field are added only to the head of the BCH at the head of the frame. For this reason, the receiving side can detect the head of the MAC frame by detecting the preamble A field and the B field.
[0009]
A transmission / reception operation in the AP and MT will be described with reference to FIGS.
When data requiring transmission is received from the Ethernet network 8, the data is converted in the CL unit (convergence layer data conversion unit) 5 and stored in the transmission buffer unit 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 transmitted. PHY unit 3 And sent out through the RF unit 7 and the antenna unit 4. The reception PHY unit 12 performs decoding processing on the received encoded data according to the encoding mode described in the scheduling data buffer unit 9 via the antenna unit 4 and the RF unit 7, and 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. Data stored in the reception buffer unit 13 is converted in format by the CL unit 5 and sent to the Ethernet network 8.
[0010]
In MT 202, the bandwidth allocation request for data transmission from MT 202 is raised to AP 201. In the AP 201, the scheduling unit 14 allocates a band for each MAC frame based on a band necessary for data transmission from the own AP 201 to each MT and a band allocation request from each MT, 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 its own MT in the scheduling data buffer unit 9 among the scheduling information described in the received FCH. AP and MT perform transmission / reception timing 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.
[0011]
[Problem to be Solved by the Invention]
Since the wireless 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 prolonged use time of the MT.
[0012]
Usually, a necessary circuit voltage is supplied during communication between the MT and the AP. On the other hand, in the power consumption reduction process in the standby state (hereinafter referred to as battery saving), the power supply to unnecessary circuits is stopped (sleep state), and the cycle (number of sleep frames) determined between APs The voltage is supplied only when it is confirmed whether there is an access request from the AP (sleep release check process). Thereby, power consumption in the standby state is reduced.
[0013]
The process in battery saving is demonstrated using FIG.
When it is determined that the standby state continues and the transition to the sleep state is made, the MAC unit 6 sends the sleep request and the requested number of sleep frames to the AP via the transmission PHY unit 3. Upon receiving a sleep permission signal including the number of permitted sleep frames and the number of frames for synchronization adjustment from the AP, the MAC unit 6 sets a value corresponding to the number of frames for synchronization adjustment in the timer count calculation unit 107, The operation clock and timer count to be used are calculated from the number of frames set by the timer count calculation unit 107, set in the sleep timer unit 106, and temporarily enter the sleep state. The sleep timer unit 106 operates with the set operation clock, and inputs a processing request to the sleep operation processing unit 103 after the set timer count. The sleep operation processing unit 103 starts a sleep release check process, and the frame synchronization detection unit 109 searches for the head of the frame based on the preamble A field and B field located at the head of the frame. When the frame synchronization detection unit 109 detects the head of the frame, the decoding processing unit 108 decodes the BCH data received subsequently. The BCH is sent to the BCH reception buffer unit 102, and the BCH data analysis unit 101 determines from the AP identifier and frame number described in the BCH whether it is the target frame of the target AP. If they do not match, the frame synchronization detection unit 109 continues to detect the beginning of the frame. If they match, the presence / absence flag for bandwidth allocation to the sleeping MT described in BCH is confirmed. If the flag is on (allocation), an FCH reception request is sent to the MAC unit 6. The MAC unit 6 sets reception of the FCH in the transmission / reception scheduling 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 band 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 sleep. When the received data determination unit 104 determines that there is no allocation, or when the BCH data analysis unit 101 determines that there is no allocation, the sleep operation processing unit 103 continues the sleep process, and the timer count calculation unit 107 Based on the calculation result of the timer count calculation unit 107, the sleep timer unit 106 is activated and enters the sleep state. Note that 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 transmits a bandwidth allocation request for information transmission to the AP using the RCH. In response to the bandwidth allocation request, the MT is released from sleep.
[0014]
As a result, it is possible to reduce wasteful power consumption in the standby state, and as a result, increase the usage time. Furthermore, the power consumption as a whole can be reduced by minimizing the power supply and clock supply circuits according to the processing state such as sleep state, frame synchronization detection, and BCH data analysis processing. It becomes.
[0015]
When a user uses a wireless terminal station, there is a high possibility that data will be transmitted / received. Therefore, it is necessary to establish a wireless connection so that data can be immediately transmitted / received. On the other hand, as the time during which the user is not using the terminal becomes longer, the possibility of data transmission / reception becomes lower. To reduce power consumption. However, the number of sleep frames in battery saving is determined by exchanging the sleep setting between the MT and the AP in order for the MT to enter the sleep state. Normally, the MT exchanges with the AP when entering the sleep state. It will be used without changing the number of sleep frames. For this reason, when the possibility of use is very low, for example, even when the unused time is very long, power consumption based on the number of sleep frames determined at the time of transition to the sleep state is consumed. Therefore, there is a tendency to consume power wastefully.
An object of the present invention is to further reduce power consumption when a terminal is not used for a long time in a wireless access system.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, in a wireless terminal station that wirelessly transmits and receives information to and from a wireless base station, a standby state continues and a sleep state in which power supply to unnecessary circuits is stopped . The sleep processing unit that processes the sleep operation, and the sleep processing unit lengthens the sleep operation when the unused state has elapsed for a predetermined time longer than a predetermined time during the sleep state. Thus, the gist is that the power consumption is reduced.
[0017]
According to the invention of claim 2, in a wireless terminal station that transmits / receives information to / from a wireless base station wirelessly and is supplied with power from another device, the standby state continues and power supply to unnecessary circuits is stopped. A sleep processing unit that processes the sleep operation when the transition to the sleep state is determined. When the elapsed time of the unused state becomes longer than a predetermined time during the sleep state, the sleep processing unit The gist is that the power consumption of the power supply of the other device is reduced by lengthening the operation.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, based on one Example of this invention, it demonstrates using figures. In addition, the same code | symbol is used for the location which shows the same structure.
FIG. 1 is a basic configuration diagram relating to a sleep processing unit according to an embodiment of the present invention.
When it is determined that the standby state continues and the sleep state is entered, the MAC unit 6 sends the sleep request and the number of requested sleep frames to the AP via the transmission PHY unit 3. Upon receiving a sleep permission signal including the number of permitted sleep frames and the number of frames for synchronization adjustment from the AP, the MAC unit 6 sets a value corresponding to the number of frames for synchronization adjustment in the timer count calculation unit 107, The operation clock and timer count to be used are calculated from the number of frames set by the timer count calculation unit 107, set in the sleep timer unit 106, and temporarily enter the sleep state. The sleep timer unit 106 operates with the set operation clock, and inputs a processing request to the sleep operation processing unit 103 after the set timer count. The sleep operation processing unit 103 starts a sleep release check process, and the frame synchronization detection unit 109 searches for the head of the frame based on the preamble A field and B field located at the head of the frame. When the frame synchronization detection unit 109 detects the head of the frame, the decoding processing unit 108 decodes the BCH data received subsequently. The BCH is sent to the BCH reception buffer unit 102, and the BCH data analysis unit 101 determines from the AP identifier and frame number described in the BCH whether it is the target frame of the target AP. If they do not match, the frame synchronization detection unit 109 continues to detect the beginning of the frame. If they match, the presence / absence flag for bandwidth allocation to the sleeping MT described in BCH is confirmed. If the flag is on (allocation), an FCH reception request is sent to the MAC unit 6. The MAC unit 6 sets reception of the FCH in the transmission / reception scheduling 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 band 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 sleep. When the received data determination unit 104 determines that there is no allocation, or when the BCH data analysis unit 101 determines that there is no allocation, the sleep operation processing unit 103 continues the sleep process, and the timer count calculation unit 107 Based on the calculation result of the timer count calculation unit 107, the sleep timer unit 106 is activated and enters the sleep state. Note that, 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 transmits a bandwidth allocation request for information transmission to the AP using the RCH. Receives the bandwidth allocation request and recognizes that the MT is released from sleep.
[0022]
The sleep operation processing unit 103 includes a sleep frame calculation unit 152 and a sleep control unit 143. The sleep frame calculation unit 152 calculates the number of sleep frames based on the elapsed time information 151 in the unused state. The calculated number of sleep frames is sent to the MAC unit 6 via the sleep control unit 153 and sent to the AP together with the sleep request. In the sleep state, when the sleep control unit 153 determines from the calculation result of the sleep frame calculation unit 152 that the possibility of use has further decreased, the sleep control unit 153 sends a bandwidth allocation request to the AP to change the number of sleep frames. Then, a sleep request is sent to the AP together with the calculated number of sleep frames. Note that the measurement of the elapsed time information 151 in the unused state may be any of measurement means provided in a device (for example, a personal computer) connected to the wireless terminal station or measurement means provided in the wireless terminal station.
[0023]
FIG. 7 is an example of an unused state elapsed time-sleep frame number graph in the sleep processing unit according to the embodiment of the present invention.
The vertical axis represents the number of sleep frames, and the direction of the arrow is the direction in which the number of sleep frames increases. The horizontal axis is the elapsed time in the unused state, and the direction of the arrow is the direction in which the elapsed time increases. The solid line indicates the number of sleep frames used in the present invention, and the thick broken line indicates the conventional setting of the number of sleep frames. The elapsed time Ta indicates the elapsed time for shifting to the sleep state, and the elapsed time Tb indicates the elapsed time for shifting to the sleep state and the elapsed time for determining that the possibility of use has further decreased. The elapsed time in the unused state is the elapsed time from the last input from the man-machine interface by the user.
[0024]
In FIG. 7, in the conventional setting of the number of sleep frames, the number of sleep frames is set by shifting to the sleep state at the elapsed time Ta in the unused state. However, the number of sleep frames does not change thereafter. On the other hand, in the setting of the number of sleep frames according to the present invention, the number of sleep frames is increased at the elapsed time Tb. That is, if it is determined that the possibility of use is further low during the sleep state, power consumption is reduced.
[0025]
When the device connected to this wireless terminal station is a personal computer, etc., and the power is supplied from the personal computer, the elapsed time of the unused state of the MP when the personal computer is powered from the battery inside the personal computer Based on the above, by changing the number of sleep frames, the consumption current of a connected device such as a personal computer can be reduced and the usage time can be extended. Furthermore, the number of sleep frames of this wireless terminal station is updated in conjunction with the power shut-off time (eg, monitor power off, hard disk power off, etc.) in the power management of the connected device such as a personal computer. Also good. In addition, although it has been described that the determination of the state (Ta, Tb) from the elapsed time of the unused state and the calculation of the number of sleep frames based on the determination are performed inside the wireless terminal station, these are performed inside the connected device. It shall be good.
[0026]
【Effect of the invention】
As described above, according to the present invention, it is possible to further reduce the power consumption by increasing the number of sleep frames as the elapsed time of the unused state increases, and to increase the usage time. And In addition, since the number of sleep frames can be updated according to the power supply of the device connected to the wireless terminal station, the load on the internal battery of the connected device is reduced and the device is supplied externally. Can ensure the same responsiveness as before.
[Brief description of the drawings]
FIG. 1 is a basic configuration diagram relating to a sleep processing unit according to an embodiment of the present invention;
FIG. 2 is a frame structure diagram of MMAC.
FIG. 3 is a configuration diagram of a BCH.
FIG. 4 is a schematic diagram of a configuration of a radio base station (AP).
FIG. 5 is a schematic diagram of a configuration of a wireless terminal station (MT).
FIG. 6 is a basic configuration diagram of a conventional sleep processing unit.
FIG. 7 is an example of a graph of an elapsed time in an unused state−the number of sleep frames in a sleep processing unit according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Transmission buffer part 2 Transmission DLC part 3 Transmission PHY part 4 Antenna part 5 CL part 6 MAC part 7 RF part 8 Ethernet network 9 Transmission / reception scheduling data buffer part 10 Reception DLC part 11 Sleep processing part 12 Reception PHY part 13 Reception buffer part 14 Scheduling unit 15 MAC unit 101 BCH data analysis 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 107 Timer count calculation unit 108 Decoding processing unit 109 Frame synchronization detection unit 151 Not yet Usage state elapsed time information 152 Sleep frame calculation unit 153 Sleep control unit 201 AP (radio base station)
202 MT (wireless terminal station)

Claims (2)

In a wireless terminal station that transmits and receives information wirelessly with a wireless base station,
When the standby state continues and the transition to the sleep state for stopping the supply of power to unnecessary circuits is determined, the sleep processing unit that processes the sleep operation,
The sleep processing unit is configured to reduce power consumption by extending the sleep operation when an elapsed time in an unused state becomes longer than a predetermined time during the sleep state. Terminal station. In a wireless terminal station that transmits and receives information wirelessly with a wireless base station and is supplied with power from another device,
When the standby state continues and the transition to the sleep state for stopping the supply of power to unnecessary circuits is determined, the sleep processing unit that processes the sleep operation,
The sleep processing unit is configured to reduce power consumption of the power supply of the other device by extending the sleep operation when the elapsed time of the unused state becomes longer than a predetermined time during the sleep state. A wireless terminal station characterized by that.

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