WO2010002036A1

WO2010002036A1 - Control apparatus, communication apparatus, communication method and integrated circuit for power saving

Info

Publication number: WO2010002036A1
Application number: PCT/JP2009/062486
Authority: WO
Inventors: Hironori Tanaka
Original assignee: Panasonic Corporation
Priority date: 2008-07-02
Filing date: 2009-07-02
Publication date: 2010-01-07
Also published as: JP2010016505A

Abstract

A control apparatus includes: a receiver which is adapted to receive from a communication apparatus first data free of a power saving request or second data including the power saving request; a schedule setting unit which is adapted to set third data having a first time period in a case where the receiver receives the first data, and to set fourth data having a second time period shorter in time length than the first time period in a case where the receiver receives the second data; and a transmitter which is adapted to transmit to the communication apparatus the third data or the fourth data set by the schedule setting unit.

Description

DESCRIPTION

CONTROL APPARATUS, COMMUNICATION APPARATUS, COMMUNICATION METHOD AND INTEGRATED CIRCUIT

Technical Field

The present invention relates to a control apparatus which is used in wireless communications such as WiMAX (Worldwide Interoperability for

Microwave Access) to control wireless communication medium, a communication apparatus, a communication method and an integrated circuit used in the control apparatus.

Background Art

In recent years, various types of wireless communication networks have been well organized and connection to networks by mobile communications using portable wireless communication apparatuses is now a general practice.

However, because there is a difficulty with providing a constant supply of electric power from and outlet of a commercial power supply, in general, for a portable wireless communications device used in mobile communications, a battery accumulator which can be charged from a commercial power supply is used as a driving source. However, where a battery is decreased in remaining battery level on the move or at a destination, an outlet of commercial power supply is not always readily available, and there may be a difficulty in charging the battery.

Citation List

Patent Literature

[Patent Literature 1 ] Japanese Patent No. 3410892

Summary of Invention The present invention has been made in view of the above situation, an object of which is to provide a control apparatus, a communication apparatus, a communication method and an integrated circuit which make it possible to save a greater extent the electric power consumption of the communication apparatus whose battery is decreased in remaining battery level than usual in an access control system of control apparatus centralized administration.

An aspect of the present invention provides a control apparatus, including: a receiver which is adapted to receive from a communication apparatus first data free of a power saving request or second data including the power saving request; a schedule setting unit which is adapted to set third data having a first time period in a case where the receiver receives the first data, and to set fourth data having a second time period shorter in time length than the first time period in a case where the receiver receives the second data; and a transmitter which is adapted to transmit to the communication apparatus the third data or the fourth data set by the schedule setting unit.

Another aspect of the present invention provides a control apparatus, including: receiving means for receiving from a communication apparatus first data free of a power saving request or second data including the power saving request; schedule setting means for setting third data having a first time period in a case where the receiving means receives the first data, and setting fourth data having a second time period shorter in time length than the first time period in a case where the receiving means receives the second data; and transmitting means for transmitting to the communication apparatus the third data or the fourth data set by the schedule setting means.

Still another aspect of the present invention provides a communication method, including: receiving from a communication apparatus first data free of a power saving request or second data including the power saving request; setting third data having a first time period in a case where the first data is received, and setting fourth data having a second time period shorter in time length than the first time period in a case where the second data is received; and transmitting to the communication apparatus the set third data or the set fourth data. Still another aspect of the present invention provides an integrated circuit, including: a receiver which is adapted to receive from a communication apparatus first data free of a power saving request or second data including the power saving request; a schedule setting unit which is adapted to set third data having a first time period in a case where the receiver receives the first data, and to set fourth data having a second time period shorter in time length than the first time period in a case where the receiver receives the second data; and a transmitter which is adapted to transmit to the communication apparatus the third data or the fourth data set by the schedule setting unit.

According to the present invention, upon transmission of first data to be transmitted to a communication apparatus, a control apparatus analyzes second data transmitted from the communication apparatus and sets a time period of the first data on the basis of the analysis result. Therefore, it is possible to make communications depending on a use status of the communication apparatus. For example, in a case where the communication apparatus requests power saving, communications can be made so as to suppress the electric power consumption of the communication terminal device.

Brief Description of Drawings

Fig. 1 is a perspective view of appearance showing a control apparatus (front face). Fig. 2 is a perspective view of appearance of the control apparatus (back face).

Fig. 3 is a block diagram showing one example of hardware of the control apparatus.

Fig. 4 is a perspective view of appearance showing a communication apparatus.

Fig. 5 is a functional block diagram of the control apparatus in a first embodiment and a second embodiment.

Fig. 6 is a functional block diagram of the control apparatus in a third embodiment. Fig. 7 is a frame configuration diagram of a communication system in the first embodiment.

Fig. 8 is a frame configuration diagram of a communication system in the second embodiment.

Fig. 9 is a frame configuration diagram of a communication system in the third embodiment.

Fig. 10 is a frame configuration diagram of a communication system in normal operation.

Fig. 11 is a configuration diagram of the communication system in the first embodiment, the second embodiment and the third embodiment.

Description of Embodiments

A first aspect provides a control apparatus, including: a receiver which is adapted to receive from a communication apparatus first data free of a power saving request or second data including the power saving request; a schedule setting unit which is adapted to set third data having a first time period in a case where the receiver receives the first data, and to set fourth data having a second time period shorter in time length than the first time period in a case where the receiver receives the second data; and a transmitter which is adapted to transmit to the communication apparatus the third data or the fourth data set by the schedule setting unit. According to the constitution, where second data including a power saving request is received from the communication apparatus, a time period of fourth data to be transmitted to the communication apparatus is set to a second time period shorter in time length. Therefore, it is possible to reduce the time necessary for activating the communication apparatus for a power saving request to receive the fourth data and also to suppress the electric power consumption of the communication apparatus.

A second aspect provides a control apparatus, wherein the schedule setting unit sets a time period of fifth data to be received next time from the communication apparatus to a third time period in a case where the transmitter transmits the third data, and sets a time period of sixth data to be received next time from the communication apparatus to a fourth time period shorter in time length than the third time period in a case where the transmitter transmits the fourth data.

According to the constitution, since a time period of sixth data to be transmitted to the control apparatus by the communication apparatus for a power saving request is set to a fourth time period shorter in time length, it is possible to reduce the time for activating the communication apparatus to transmit the sixth data and also to suppress the electric power consumption of the communication apparatus. A third aspect provides a control apparatus, wherein the schedule setting unit sets a first frequency width with respect to the third data in a case where the receiver receives the first data, and sets a second frequency width greater in width than the first frequency width to the fourth data in a case where the receiver receives the second data. According to the constitution, since a frequency width of fourth data which is decreased in time length is set to a second frequency width larger in frequency width, it is possible to make communications without lowering the transmission rate, even where the fourth data is set to be shorter in time period.

A fourth aspect provides a control apparatus, wherein the schedule setting unit sets a frequency width of fifth data to be received next time from the communication apparatus to a third frequency width in a case where the transmitter receives the third data, and sets a frequency width of sixth data to be received next time from the communication apparatus to a fourth frequency width greater in width than the third frequency width in a case where the transmitter transmits the fourth data. According to the constitution, since a frequency width of sixth data which is decreased in time length is set to a fourth frequency width larger in frequency width, it is possible to make communications without lowering the transmission rate, even where the sixth data is set to be shorter in time period.

A fifth aspect provides a control apparatus, wherein the schedule setting unit sets a schedule for transmitting the sixth data adjacent to a schedule for transmitting the fourth data.

According to the constitution, time for transmitting the fourth data from the control apparatus to the communication apparatus is allowed to be continuous to time for transmitting the fourth data from the communication apparatus to the control apparatus. Therefore, since the communication apparatus is able to transmit and receive the data without switching off a power supply between receipt of the fourth data and transmission of sixth data, it is possible to reduce the electric power consumption of the communication apparatus. A sixth aspect provides a control apparatus, wherein the power saving request is information indicating a remaining battery level of the communication apparatus.

A seventh aspect provides a control apparatus, wherein: the receiver receives seventh data including a power saving request from an other communication apparatus; the transmitter transmits eighth data having a fifth time period to the other communication apparatus in a case where the receiver receives the seventh data; the control apparatus further comprises a comparison unit which is adapted to compare first information contained in the second data to indicate a remaining battery level of the communication apparatus with second information contained in the seventh data to indicate a remaining battery level of the other communication apparatus; and the schedule setting unit sets the second time period to be greater in time length than the fifth time period in a case where the first information is greater than the second information, and sets the second time period to be smaller in time length than the fifth time period in a case where the first information is smaller than the second information.

According to the constitution, since a shorter time period can be set to a communication apparatus whose battery is further decreased in remaining battery level, it is possible to further reduce the electric power consumption of the communication apparatus.

An eighth aspect provides a control apparatus, further including an assignment unit which is adapted to assign information indicating the first time period set by the schedule setting unit to the third data, and to assign information indicating the second time period set by the schedule setting unit to the fourth data.

According to the constitution, it is possible to notify the communication apparatus of information indicating a first time period and information indicating a second time period newly set by the schedule setting unit.

A ninth aspect provides a communication apparatus for receiving the first data transmitted from the control apparatus, the communication apparatus including: a receiver which is adapted to receive one of the third data and the fourth data; and a setting unit which is adapted to set the third time period to the fifth data on the basis of information indicating the first time period upon receipt of the third data, and to set the fourth time period to the sixth data on the basis of information indicating the second time period upon receipt of the fourth data.

According to the constitution, since the communication apparatus is able to transmit the fifth data and the sixth data according to the third time period and the fourth time period set by the schedule setting unit of the control apparatus, it is possible to reduce the electric power consumption of the communication apparatus.

A tenth aspect provides a communication apparatus, further including: an assignment unit which is adapted to assign a power saving request to the second data to be transmitted to the control apparatus; and a transmitter which is adapted to transmit the second data to which the power saving request is assigned.

According to the constitution, it is possible to reduce the electric power consumption of the communication apparatus by notifying the control apparatus of a power saving request.

An eleventh aspect provides a communication apparatus, further including: a battery for supplying electric power to the communication apparatus; and a remaining battery level detector which is adapted to detect a remaining battery level of the battery, wherein the assignment unit assigns information indicating the remaining battery level to the power saving request. According to the constitution, information indicating the remaining battery level is assigned to a power saving request and the power saving request is notified to the control apparatus. It is, thereby, possible to reduce the electric power consumption of the communication apparatus. A twelfth aspect provides a control apparatus, including: receiving means for receiving from a communication apparatus first data free of a power saving request or second data including the power saving request; schedule setting means for setting third data having a first time period in a case where the receiving means receives the first data, and setting fourth data having a second time period shorter in time length than the first time period in a case where the receiving means receives the second data; and transmitting means for transmitting to the communication apparatus the third data or the fourth data set by the schedule setting means.

According to the constitution, where second data including a power saving request is received from the communication apparatus, a time period of fourth data to be transmitted to the communication apparatus is set to a second time period shorter in time length. Therefore, it is possible to reduce the time necessary for activating the communication apparatus for a power saving request to receive the fourth data and also to suppress the electric power consumption of the communication apparatus.

A thirteenth aspect provides a control apparatus, wherein the schedule setting means sets a time period of fifth data to be received next time from the communication apparatus to a third time period in a case where the transmitting means transmits the third data, and sets a time period of sixth data to be received next time from the communication apparatus to a fourth time period shorter in time length than the third time period in a case where the transmitting means transmits the fourth data.

According to the constitution, since a time period of sixth data to be transmitted to the control apparatus by the communication apparatus for a power saving request is set to a fourth time period shorter in time length, it is possible to reduce the time for activating the communication apparatus to transmit the sixth data and also to suppress the electric power consumption of the communication apparatus.

A fourteenth aspect provides a control apparatus, wherein the schedule setting means sets a first frequency width with respect to the third data in a case where the receiving means receives the first data, and sets a second frequency width greater in width than the first frequency width to the fourth data in a case where the receiving means receives the second data.

According to the constitution, since a frequency width of fourth data which is decreased in time length is set to a second frequency width larger in frequency width, it is possible to make communications without lowering the transmission rate, even where the fourth data is set to be shorter in time period.

A fifteenth aspect provides a control apparatus, wherein the schedule setting means sets a frequency width of fifth data to be received next time from the communication apparatus to a third frequency width in a case where the transmitting means receives the third data, and sets a frequency width of sixth data to be received next time from the communication apparatus to a fourth frequency width greater in width than the third frequency width in a case where the transmitting means transmits the fourth data.

According to the constitution, since a frequency width of sixth data which is decreased in time length is set to a fourth frequency width larger in frequency width, it is possible to make communications without lowering the transmission rate, even where the sixth data is set to be shorter in time period.

A sixteenth aspect provides a control apparatus, wherein the schedule setting means sets a schedule for transmitting the sixth data adjacent to a schedule for transmitting the fourth data.

According to the constitution, time for transmitting the fourth data from the control apparatus to the communication apparatus is allowed to be continuous to time for transmitting the fourth data from the communication apparatus to the control apparatus. Therefore, since the communication apparatus is able to transmit and receive the data without switching off a power supply between receipt of the fourth data and transmission of sixth data, it is possible to reduce the electric power consumption of the communication apparatus.

A seventeenth aspect provides a control apparatus, wherein the power saving request is information indicating a remaining battery level of the communication apparatus.

An eighteenth aspect provides a control apparatus, wherein: the receiving means receives seventh data including a power saving request from an other communication apparatus; the transmitting means transmits eighth data having a fifth time period to the other communication apparatus in a case where the receiving means receives the seventh data; wherein the control apparatus further includes comparison means for comparing first information contained in the second data to indicate a remaining battery level of the communication apparatus with second information contained in the seventh data to indicate a remaining battery level of the other communication apparatus; and the schedule setting means sets the second time period to be greater in time length than the fifth time period in a case where the first information is greater than the second information, and sets the second time period to be smaller in time length than the fifth time period in a case where the first information is smaller than the second information. According to the constitution, since a shorter time period can be set to a communication apparatus whose battery is further decreased in remaining battery level, it is possible to further reduce the electric power consumption of the communication apparatus.

A nineteenth aspect provides a control apparatus, further including assignment means for assigning information indicating the first time period set by the schedule setting means to the third data, and assigning information indicating the second time period set by the schedule setting means to the fourth data.

A twentieth aspect provides a communication apparatus for receiving the first data transmitted from the control apparatus, the communication apparatus including: receiving means for receiving one of the third data and the fourth data; and setting means for setting the third time period to the fifth data on the basis of information indicating the first time period upon receipt of the third data, and setting the fourth time period to the sixth data on the basis of information indicating the second time period upon receipt of the fourth data.

A twenty-first aspect provides a communication apparatus, further including: assignment means for assigning a power saving request to the second data to be transmitted to the control apparatus; and transmitting means for transmitting the second data to which the power saving request is assigned.

According to the constitution, it is possible to reduce the electric power consumption of the communication apparatus by notifying the control apparatus of a power saving request. A twenty-second aspect provides a communication apparatus, further including: a battery for supplying electric power to the communication apparatus; and remaining battery level detecting means for detecting a remaining battery level of the battery, wherein the assignment means assigns information indicating the remaining battery level to the power saving request. According to the constitution, information indicating the remaining battery level is assigned to a power saving request and the power saving request is notified to the control apparatus. It is, thereby, possible to reduce the electric power consumption of the communication apparatus.

A twenty-third aspect provides a communication method, including: receiving from a communication apparatus first data free of a power saving request or second data including the power saving request; setting third data having a first time period in a case where the first data is received, and setting fourth data having a second time period shorter in time length than the first time period in a case where the second data is received; and transmitting to the communication apparatus the set third data or the set fourth data.

A twenty-fourth aspect provides a communication method, wherein a time period of fifth data to be received next time from the communication apparatus is set to a third time period in a case where the third data is transmitted, and a time period of sixth data to be received next time from the communication apparatus is set to a fourth time period shorter in time length than the third time period in a case where the fourth data is transmitted.

A twenty-fifth aspect provides a communication method, wherein a first frequency width with respect to the third data is set in a case where the first data is received, and a second frequency width greater in width than the first frequency width is set to the fourth data in a case where the second data is received.

A twenty-sixth aspect provides a communication method, wherein a frequency width of fifth data to be received next time from the communication apparatus is set to a third frequency width in a case where the third data is transmitted, and a frequency width of sixth data to be received next time from the communication apparatus is set to a fourth frequency width greater in width than the third frequency width in a case where the fourth data is transmitted.

A twenty-seventh aspect provides a communication method, wherein a schedule for transmitting the sixth data is set adjacent to a schedule for transmitting the fourth data.

A twenty-eighth aspect provides a communication method, wherein the power saving request is information indicating a remaining battery level of the communication apparatus. A twenty-ninth aspect provides a communication method, including: receiving seventh data including a power saving request from an other communication apparatus; transmitting eighth data having a fifth time period to the other communication apparatus in a case where the seventh data is received; comparing first information contained in the second data to indicate a remaining battery level of the communication apparatus with second information contained in the seventh data to indicate a remaining battery level of the other communication apparatus; and setting the second time period to be greater in time length than the fifth time period in a case where the first information is greater than the second information, and setting the second time period to be smaller in time length than the fifth time period in a case where the first information is smaller than the second information.

A thirtieth aspect provides a communication method, further including assigning information indicating the first time period to the third data, and assigning information indicating the second time period to the fourth data. According to the constitution, it is possible to notify the communication apparatus of information indicating a first time period and information indicating a second time period newly set by the schedule setting unit.

A thirty-first aspect provides an integrated circuit, including: a receiver which is adapted to receive from a communication apparatus first data free of a power saving request or second data including the power saving request; a schedule setting unit which is adapted to set third data having a first time period in a case where the receiver receives the first data, and to set fourth data having a second time period shorter in time length than the first time period in a case where the receiver receives the second data; and a transmitter which is adapted to transmit to the communication apparatus the third data or the fourth data set by the schedule setting unit.

Hereinafter, embodiments will be described by reference to drawings. (First embodiment) A description will be given of a first embodiment by reference to Figs. 1 ,

2, 3, 4, 5, 7, 10 and 11.

Fig. 1 is a perspective view of appearance showing the front face of one example of a control apparatus. Fig. 2 is a perspective view of appearance showing the back face of one example of the control apparatus. As shown in Fig. 1 , a control apparatus 1 of the first embodiment is a small-sized femtocell to manage several communication apparatuses. The control apparatus 1 has a housing 11 , and a display unit 12 such as an LED (Light Emitting Diode) is installed on the front face of the housing 11. As shown in Fig. 2, a DC power supply connector 13, a LAN modular jack 14 such as RJ45, and a WAN (Wide Area Network) modular jack 15 are installed on the back face of the housing 11. As shown in Fig. 2, an electric power line 16 such as a parallel cable is connected to the DC power supply connector 13. A LAN cable 17 is connected to the LAN modular jack 14 and the WAN modular jack 15. It is noted that the femtocell in Fig. 1 and Fig. 2 is given as an example of the control apparatus. The control apparatus shall not be, however, limited thereto and any control apparatus may be acceptable as long as it has functions of a base station for controlling communication apparatuses.

Fig. 3 is a block diagram showing one example of hardware of the control apparatus. As shown in Fig. 3, the control apparatus 1 is provided with a circuit module 110 inside the housing 11 which is indicated by the broken line. A main IC 111 , a wireless controller 119 and a wireless module 120 are mounted on the circuit module 110.

The main IC 111 is provided with a CPU 111 a, buses such as a main bus 111f and a local bus 111g, a BCU (Bus Control Unit) 111 b for controlling the flow of data on the bus, MAC blocks (EMAC) 111c, 111 d for controlling a MAC layer of Ethernet (registered trade mark) and a PCIU 111 e for controlling and a PCI (Peripheral Component Interconnect Unit) bus.

The CPU 111a and the BCU 111 b inside the main IC 111 are connected via the main bus 111f to an SDRAM 114 and a Flash ROM 115. Further, the CPU 111 a and the BCU 111 b are connected via the local bus 111g to an oscillator 112 for supplying a clock to the main IC 111 , a display unit 12 such as an LED, and a reset IC 113 for outputting a reset signal to the main IC 111.

Inside the main IC 111 , 111 c and 111 d are EMACs (Ethernet (registered trademark) Media Access Controller) for controlling the MAC layer of Ethernet (registered trademark). The EMACs 111c, 111d are respectively connected to EPHY (Ethernet (registered trademark) PHYsical layer) 116, 117 for controlling a physical layer of the Ethernet (registered trademark), and the EPHY 116, 117 are respectively connected to a LAN modular jack 14 and a WAN modular jack 15. Further, the main IC 111 is connected via a DC-DC converter 118 to a DC power supply connector 13. The DC-DC converter 118 converts a DC voltage supplied from the DC power supply connector 13 to a DC voltage necessary at the main IC 111.

The wireless controller 119 is provided with a MAC block 119a for controlling the MAC layer and a PHY block 119b for controlling the physical layer. The PCIU 111 e inside the main IC 111 is connected via the MAC block 119a to the PHY block 119b.

The wireless module 120 is set in a transmitting state or a receiving state from the main IC 111 and provided with transmitting-receiving switching SW 120a and SW 120b, LNA 120c and LNA 12Od for amplifying a received signal, PA 12Oe and PA 12Of for amplifying a transmitted signal and an RF modulator-demodulator 12Og for performing modulation to a radio signal and demodulation from a radio signal.

The wireless module 120 is connected to the oscillator 121 for supplying a clock to the wireless module 120 and the RF modulator-demodulator 12Og inside the wireless module 120 is connected to the PHY block 119b inside the wireless controller 119. The transmitting-receiving switching SW 120a and SW 120b inside the wireless module 120 are connected to antennas 123, 124.

Fig. 4 is a perspective view of appearance showing one example of the communication apparatus. As shown in Fig. 4, communication apparatuses 2a, 2b, 2c, 2d and 2e given in the first embodiment are portable phones. The communication apparatuses 2a, 2b, 2c, 2d and 2e have a housing 201 , respectively. The housing 201 is provided with an LCD (Liquid Crystal Display) 202 for displaying a telephone number and others, a key matrix 203 made up of buttons and others for designating a telephone number, a microphone 204, an external antenna 205 for transmitting and receiving radio waves, and a loud speaker 206 for outputting voice from a counterpart loud speaker. It is noted that although the phone device in Fig. 4 is given as one example of the communication apparatus, the communication apparatus shall not be limited to a telephone in particular and may be a device (an electronic device such as a personal computer) having functions connectable to a control apparatus.

Although a block diagram of hardware of the communication apparatuses 2a, 2b, 2c, 2d and 2e is omitted, hardware such as a transceiver circuit for transmitting and receiving data from a control apparatus 1 , an analysis circuit for analyzing a transmitting-receiving schedule set by the control apparatus 1 from the data received by the transceiver circuit, a control circuit for setting the transmitting-receiving schedule analyzed by the analysis circuit to the transceiver circuit, thereby conducting transmitting and receiving operations, and a battery control circuit for controlling a remaining battery level of a battery which supplies electric power to the communication apparatuses 2a, 2b, 2c, 2d and 2e are provided. The transceiver circuit assigns remaining battery level information indicating the remaining battery level obtained from the battery control circuit to data addressed to the control apparatus 1 , thereby transmitting the data to which the remaining battery level information is assigned.

Fig. 5 is a functional block diagram of the control apparatus 1 in the first embodiment. As shown in Fig. 5, the control apparatus 1 is provided with a transmitter 150, a receiver 160, a transmission packet generator 119a1 , a packet content reading unit 119a2, a main control unit 111a1 and a power saving detector 111a2. The transmission packet generator 119a 1 and the packet content reading unit 119a2 are a part of the wireless controller 119. The main control unit 111a1 and the power saving detector 111a2 are a part of the CPU 111 a. The transmitter 150 and the receiver 160 are provided with the wireless module 120, the oscillator 121 , the antenna 123 and the antenna 124.

Fig. 11 is a configuration diagram showing a communication system of the first embodiment. In the first embodiment, the control apparatus is constituted with one unit of control apparatus 1 and the communication apparatus is constituted with five units of communication apparatuses 2a, 2b, 2c, 2d and 2e. Although not depicted in Fig. 11 , the control apparatus 1 is connected to a wired LAN. Respective wireless communication channels 3a, 3b, 3c, 3d and 3e are actually not visible. More specifically, a wireless communication channel 3a is a channel between the control apparatus 1 and the communication apparatus 2a, a wireless communication channel 3b is a channel between the control apparatus 1 and the communication apparatus 2b, a wireless communication channel 3c is a channel between the control apparatus 1 and the communication apparatus 2c, a wireless communication channel 3d is a channel between the control apparatus 1 and the communication apparatus 2d, and a wireless communication channel 3e is a channel between the control apparatus 1 and the communication apparatus 2e.

A frame configuration on a normal operation of the above constituted communication system will be described by reference to Fig. 10. The frame configuration is set with a schedule by the CPU 111a. Fig. 10 shows one example of the frame configuration diagram on a normal operation of the communication system in the first embodiment. Frame is expressed two-dimensionally on a subchannel (frequency channel) axis in a subchannel unit and on a time axis in a symbol unit and can be arbitrarily allocated by a slot unit of one sub-channel x one symbol by the control apparatus 1. The frame is constituted with Downlink subframe which is a domain from the control apparatus 1 to the communication apparatuses 2a through 2e, TTG (Transmit/receive Transition Gap) which is switching time of the control apparatus 1 from transmitting operation to receiving operation, Uplink subframe which is a domain from the communication apparatuses 2a through 2e to the control apparatus 1 , and RTG (Receive/transmit Transition Gap) which is switching time of the control apparatus 1 from receiving operation to transmitting operation. The Downlink subframe is constituted with a preamble for obtaining synchronization, DL-MAP (Downϋnk MAP) for indicating how a domain of the Downlink subframe is allocated, UL-MAP (UpLink MAP) for indicating how a domain of the Uplink subframe is allocated, FCH (Frame Control Header) for indicating the length of DL-MAP and encoding information, and DL bursts #a, #b, #c, #d and #e allocated to the respective communication apparatuses 2a, 2b, 2c, 2d and 2e. The Uplink subframe is constituted with Ranging subchannel which is a domain for adjusting wireless parameters which are at least necessary and requesting the assignment of identification information, and UL bursts #a, #b, #c,

#d and #e to be allocated from the respective communication apparatuses 2a, 2b, 2c, 2d and 2e to the control apparatus 1.

In the first embodiment, the frame has 32 subchannels on a subchannel axis, 32 symbols with regard to Downlink subframe and 15 symbols with regard to Uplink subframe on a time axis. In the Downlink subframe, a preamble is allocated to symbol 1 by 32 slots, FCH is allocated to symbol 2 of the subchannels 1 and 2 by 2 slots, UL-MAP is allocated to symbol 2 of the subchannels 3 to 17 by 15 slots and DL-MAP is allocated to symbol 2 of the subchannels 18 to 32 by 15 slots over all the subchannels, and DL bursts #a, #b, #c, #d and #e are respectively allocated to symbols 3 to 32 by 192 slots over all the subchannels. In the Uplink subframe, UL bursts #a, #b, #c, #d and #e are respectively allocated to all the symbols of subchannels 1 to 30 by 90 slots, and Ranging subchannel is allocated to all symbols of subchannels 31 and 32 by 30 slots. Further, in the first embodiment, each symbol, TTG and RTG are equal in time, and the time of one frame is to cover 49 symbols. In the first embodiment, a description will be given of operations of a communication system where the communication apparatuses 2a and 2b are power saving communication apparatuses. The communication apparatuses 2a and 2b transmit a packet indicating that these communication apparatuses are power saving communication apparatuses when a communication path with the control apparatus 1 is opened.

In Fig. 5, the receiver 160 of the control apparatus 1 converts a received packet from an analog signal to a digital signal and delivers the converted packet to a packet content reading unit 119a2. The packet content reading unit 119a2 reads contents of the packet and delivers the contents of the packet which can be processed by the main IC 111 to a power saving detector 111 a2 and a main control unit 111a1. The power saving detector 111 a2 makes a determination from the contents of the packet on whether the communication apparatuses that transmit the packet are power saving communication apparatuses for each of the communication apparatuses and notifies the main control unit 111a1 of the determination result. The main control unit 111a1 generates DL-MAP and

UL-MAP depending on whether each of the communication apparatuses that have opened a communication path is a power saving communication apparatus, thereby allowing the transmission packet generator 119a1 to generate a schedule packet. The transmitter 150 converts the schedule packet from a digital signal to an analog signal and transmits the packet to a radio space.

The communication apparatuses 2a, 2b, 2c, 2d and 2e transmit and receive a packet at a timing which is scheduled within the DL-MAP and UL-MAP of the schedule packet received from the control apparatus 1. Further, the communication apparatuses 2a and 2b, which are power saving communication apparatuses, perform a power saving operation by switching the power off at a timing other than that scheduled for them, thereby reducing the electric power consumption.

Specific allocations of UL bursts #a, #b, #c, #d and #e and those of DL bursts #a, #b, #c, #d and #e in the first embodiment will be described by reference to Fig. 7.

5 Fig. 7 is a frame configuration diagram of the communication system in the first embodiment.

DL burst #a and UL burst #a addressed to the communication apparatus 2a are respectively decreased in time axis because the communication apparatus 2a is a power saving communication apparatus. 192 slots of0 (subchannels 1 to 32) x (symbols 3 to 8) are allocated to DL burst #a and 90 slots of (subchannel 1 to 30) x (symbols 13 to 15) are allocated to UL burst #a so that DL burst #a and UL burst #a are adjacent in time.

Similarly, DL burst #b and UL burst #b addressed to the communication apparatus 2b are respectively decreased in time axis because the 5 communication apparatus 2b is a power saving communication apparatus. 192 slots of (subchannels 1 to 32) x (symbols 26 to 32) are allocated to DL burst #b and 90 slots of (subchannels 1 to 30) x (symbols 1 to 3) are allocated to UL burst #b so that DL burst #b and UL burst #b are adjacent in time.

Since the communication apparatuses 2c, 2d and 2e, which are not o power saving communication apparatuses, are not restricted for schedules of DL bursts #c, #d, #e or those of UL bursts #c, #d, #e, they are allocated at a domain over a whole time axis other than domains allocated to the communication apparatuses 2a and 2b. 180 slots of (subchannels 1 to 10) x (symbols 9 to 26) and 12 slots of (subchannel 11) x (symbols 14 to 26), a total of 192 slots, are5 allocated to DL burst #c, and 90 slots of (subchannels 1 to 10) x (symbols 4 to 12) are allocated to UL burst #c. 6 slots of (subchannel 11 ) x (symbols 9 to 14), 180 slots of (subchannels 12 to 21 ) x (symbols 14 to 26) and 6 slots of (subchannel 11 ) x (symbols 9 to 14), a total of 192 slots, are allocated to DL burst #d. 90 slots of (subchannels 11 to 20) x (symbols 4 to 12) are allocated to0 UL burst #c. 12 slots of (subchannel 22) x (symbols 9 to 20) and 180 slots of (subchannels 23 to 32) x (symbols 9 to 26), a total of 192 slots, are allocated to DL burst #e. 90 slots of (subchannels 21 to 30) x (symbols 4 to 12) are allocated to UL burst #e.

A description will be given of effects of reducing the electric power5 consumption of the communication apparatuses 2a and 2b which are power saving communication apparatuses in the first embodiment. As described previously, although one frame time is to cover 49 symbols, time during which the communication apparatus 2a transmits and receives data covers 8 symbol times of symbol 1 to symbol 8 on Downlink subframe and 3 symbol times of symbol 13 to symbol 15 on Uplink subframe, a total of 11 symbol times. Further, since symbol 15 on Uplink subframe continues to symbol 1 on Downlink subframe of a subsequent frame across RTG, a total of 12 symbol times to which RTG is added is time during which electric power is to be supplied to the communication apparatus 2a. In addition, a normal start of transmitting and receiving operations needs power-up time. Therefore, if the power-up time is given as 1 symbol time, symbol 12 on Uplink subframe requires the supply of electric power. More specifically, power saving time during which the electric power can be switched off is to be 36 symbol times, of 1 frame 49 symbol times. Thus, if electric power that is required on transmitting and receiving operations or at power-up time is to be equal, it is possible to suppress the electric power consumption by 73.5% which accounts for 36 symbol times.

Similarly, time during which the communication apparatus 2b conducts transmitting and receiving operations is 8 symbol times of symbols 1 , 2 and symbols 27 to 32 on Downlink subframe and 3 symbol times of symbol 1 to symbol 3 on Uplink subframe, a total of 11 symbol times. Further, since symbol 32 on Downlink subframe continues to symbol 1 on Uplink subframe across TTG, a total of 12 symbol times to which TTG is added is time during which electric power is to be supplied to the communication apparatus 2b. In addition, since 2 symbol times of symbol 26 on Downlink subframe and RTG are required as power-up time, power saving time during which the electric power can be switched off is to be 35 symbol times, of 1 frame 49 symbol times. Thereby, it is possible to suppress the electric power consumption by 71.4%.

In the first embodiment, a description has been given of a case where one frame is to cover 32 subchannels on a subchannel axis, and on a time axis, in addition to 32 symbols with regard to Downlink subframe and 15 symbols with regard to Uplink subframe, 1 symbol time of TTG and that of RTG are included, and one frame time is to cover a total of 49 symbols. As a matter of course, any values are acceptable as the above values.

Further, where the number of symbols of Downlink and Uplink on a time axis is decreased in order to suppress the electric power consumption, the number of subchannels (frequency channels) can be increased to maintain the transmission efficiency of data. Still further, in the first embodiment, a description has been given of a case where the number of slots of DownLink and the number of slots of UpLink are equally allocated to each of the five communication apparatuses. As a matter of course, any number of slots may be allocated to each of the communication apparatuses.

Still further, in the first embodiment, a description has been given of a case where the control apparatus constructs a schedule packet so that a packet addressed to power saving communication apparatuses and a packet allocation domain addressed to the control apparatus of the power saving communication apparatuses may be decreased in time axis. As a matter of course, the schedule packet may be constructed so that either of the packet addressed to power saving communication apparatuses and the packet allocation domain addressed to the control apparatus of the power saving communication apparatuses may be decreased in time axis. In addition, in the first embodiment, a description has been given of a case where an equal amount of electric power is required on transmitting and receiving operations. As a matter of course, the electric power consumption can be effectively reduced even in a case where a different amount of electric power is required on transmitting and receiving operations. As described so far, the first embodiment relates to a method for controlling communication between a control apparatus using an access control system, in which packet allocation domains addressed to the communication apparatuses and a packet allocation domain addressed to the control apparatus are scheduled two-dimensionally on a subchannel axis and a time axis to transmit a schedule packet periodically, and the communication apparatuses controlled by the control apparatus. Where being notified that the communication apparatus is a power saving communication apparatus which is in the process of power saving operation, the control apparatus constructs the schedule packet so that packet allocation domains addressed to the power saving communication apparatuses and a packet allocation domain addressed to the control apparatus of the power saving communication apparatuses may be decreased in time axis, by which the power saving communication apparatuses are able to decrease the time during which the electric power is switched on. Thus, it is possible to suppress the electric power consumption of the power saving communication apparatuses.

Where an access control system used in wireless communications is CSMA/CA (Carrier Sense Multiple Access With Collision Avoidance), frame transmission from a low remaining battery level communication apparatus, the remaining battery level of which is low, and frame transmission from other devices to the low remaining battery level communication apparatus are given shorter time than usual, by which the low remaining battery level communication apparatus is able to compete with other communication apparatuses about the frame transmission more easily, and the probability that the electric power is switched on during the frame transmission by other communication apparatuses is reduced, thus making it possible to reduce the electric power consumption of the communication apparatus low in remaining battery level than usual.

However, this is not applicable to a case where the access control system is an access control system of control apparatus centralized administration which is used in WiMAX (Worldwide Interoperability for Microwave Access) and others. In this instance, the access control system of control apparatus centralized administration means an access control system in which a control apparatus for managing a communication apparatus schedules a packet allocation domain addressed to the communication apparatus and a packet allocation domain addressed to the control apparatus two-dimensionally on a subchannel axis and a time axis, thereby transmitting a schedule packet periodically.

(Second embodiment)

A description will be given of a second embodiment by reference to Fig. 5 and Fig. 8. In the second embodiment, a description will be given of operations of a communication system where communication apparatuses 2a, 2b, 2c and 2d are power saving communication apparatuses. The communication apparatuses 2a, 2b, 2c and 2d transmit a packet indicating that they are power saving communication apparatuses when a communication path with a control apparatus 1 is opened.

In Fig. 5, a power saving detector 111a2 of the control apparatus 1 notifies, from contents of the packet, a main control unit 111 a1 that the communication apparatuses 2a, 2b, 2c and 2d are power saving communication apparatuses, the main control unit 111 a1 generates DL-MAP and UL-MAP in which in a set of DL burst #a and UL burst #a, a set of DL burst #b and UL burst #b, a set of DL burst #c and UL burst #c, and a set of DL burst #d and UL burst #d, the members of each set are adjacent in time, and in a set of DL burst #a and DL burst #b, a set of UL burst #a and UL burst #b, a set of DL burst #c and DL burst #d and a set of UL burst #c and UL burst #d, the members of each set are equal in symbol time so that these four power saving communication apparatuses may be equally short in power-on time, thereby allowing a transmission packet generator 119a1 to generate a schedule packet, which are then converted by a transmitter 150 from a digital signal to an analog signal and transmitted into a radio space.

The communication apparatuses 2a, 2b, 2c, 2d and 2e transmit and receive a packet at a timing scheduled within the DL-MAP and UL-MAP received from the control apparatus 1 , and further, the communication apparatuses 2a, 2b, 2c and 2d, which are power saving communication apparatuses, perform a power saving operation at a timing other than that scheduled for them, thereby reducing the electric power consumption. A description will be given of specific allocations of UL bursts #a, #b, #c,

#d and #e and those of DL bursts #a, #b, #c, #d and #e in the second embodiment by reference to Fig. 8.

Fig. 8 is a frame configuration diagram of a communication system in the second embodiment. The time axis and the subchannel axis of the frame are the same as those in the first embodiment. Allocations of domains other than DL burst and UL burst to be allocated to each communication apparatus are also the same as those in the first embodiment.

DL burst #a and UL burst #a addressed to the communication apparatus 2a which is a power saving communication apparatus are respectively decreased in time axis, and 192 slots of (subchannels 1 to 16) x (symbols 3 to 14) are allocated to DL burst #a and 90 slots of (subchannels 1 to 15) x (symbols 10 to 15) are allocated to UL burst #a so that DL burst #a and UL burst #a are adjacent in time, and DL burst #a and DL burst #b as well as UL burst #a and UL burst #b are made equal in symbol time. Similarly, DL burst #b and UL burst #b addressed to the communication apparatus 2b, which is a power saving communication apparatus, are respectively decreased in time axis, and 192 slots of (subchannels 17 to 32) x (symbols 3 to 14) are allocated to DL burst #b and 90 slots of (subchannels 16 to 30) x (symbols 10 to 15) are allocated to UL burst #b so that DL burst #b and UL burst #b are adjacent in time, and DL burst #a and DL burst #b as well as UL burst #a and UL burst #b are made equal in symbol time. Similarly, DL burst #c and UL burst #c addressed to the communication apparatus 2c, which is a power saving communication apparatus, are respectively decreased in time axis, and 192 slots of (subchannels 1 to 16) x (symbols 21 to 32) are allocated to DL burst #c and 90 slots of (subchannels 1 to 15) x (symbols 1 to 6) are allocated to UL burst #c so that DL burst #c and UL burst #c are adjacent in time, and DL burst #c and DL burst #d as well as UL burst #c and UL burst #d are made equal in symbol time.

Similarly, DL burst #d and UL burst #d addressed to the communication apparatus 2d, which is a power saving communication apparatus, are respectively decreased in time axis, and 192 slots of (subchannels 17 to 32) x (symbols 21 to 32) are allocated to DL burst #d and 90 slots of (subchannels 16 to 30) x (symbols 1 to 6) are allocated to UL burst #d so that DL burst #d and UL burst #d are adjacent in time, and DL burst #c and DL burst #d as well as UL burst #c and UL burst #d are made equal in symbol time. DL burst #e and UL burst #e addressed to the communication apparatus

2e are allocated to a remaining domain other than those allocated to the communication apparatuses 2a, 2b, 2c and 2d. 192 slots (subchannels 1 to 32) x (symbols 15 to 20) are allocated to DL burst #e, and 90 slots of (subchannels 1 to 30) x (symbols 7 to 9) are allocated to UL burst #e. A description will be given of the effect of reducing the electric power consumption of the communication apparatuses 2a, 2b, 2c and 2d, which are power saving communication apparatuses in the second embodiment.

Time during which the communication apparatus 2a performs transmitting and receiving operations is 14 symbol times from symbol 1 to symbol 14 on Downlink subframe and 6 symbol times from symbol 10 to symbol 15 on Uplink subframe, a total of 20 symbol times. Further, since symbol 15 on Uplink subframe continues to symbol 1 on Downlink subframe of a subsequent frame across RTG, a total of 21 symbol times to which RTG is added is time during which the electric power is to be supplied to the communication apparatus 2a. In addition, symbol 9 on Uplink subframe, which is power-up time, requires the supply of electric power. More specifically, power saving time during which the electric power can be switched off is to be 27 symbol times, of 1 frame 49 symbol times. Therefore, if electric power that is required on transmitting and receiving operations or at power-up time is to be equal, it is possible to suppress the electric power consumption by 55.1 % which accounts for 27 symbol times. Since the communication apparatus 2b is also equal in power saving time to the communication apparatus 2a, it is possible to suppress the electric power consumption by 55.1 %.

Time during which the communication apparatus 2c performs transmitting and receiving operations is 14 symbol times from symbols 1 , 2 and symbols 21 to 32 on Downlink subframe and 6 symbol times from symbol 1 to symbol 6 on Uplink subframe, a total of 20 symbol times. Further, since symbol 32 on Downlink subframe continues to symbol 1 on Uplink subframe across TTG, a total of 21 symbol times to which TTG is added is time during which the electric power is to be supplied to the communication apparatus 2c. In addition, since 2 symbol times of symbol 20 on Downlink subframe and RTG are required as power-up time, power saving time during which the electric power is switched off is to be 26 symbol times, of 1 frame 49 symbol times. Thereby, it is possible to suppress the electric power consumption by 53.1 %.

Since the communication apparatus 2d is also equal in power saving time to the communication apparatus 2c, it is possible to suppress the electric power consumption by 53.1 %.

As described so far, it is possible to suppress the electric power consumption of all the communication apparatuses 2a, 2b, 2c and 2d, which are power saving communication apparatuses. In the second embodiment, a description has been given of a case where one frame is to cover 32 subchannels on a subchannel axis, and on a time axis, in addition to 32 symbols with regard to Downlink subframe and 15 symbols with regard to Uplink subframe, 1 symbol time of TTG and that of RTG are included, and one frame time is to cover a total of 49 symbols. As a matter of course, any values are acceptable as the above values.

Still further, in the second embodiment, a description has been given of a case where the number of slots of Downϋnk and the number of slots of UpLink are equally allocated to each of the five communication apparatuses. As a matter of course, any number of slots may be allocated to each of the communication apparatuses.

Still further, in the second embodiment, a description has been given of a case where the control apparatus constructs a schedule packet so that a packet addressed to the power saving communication apparatuses and a packet allocation domain addressed to the control apparatus of the power saving communication apparatuses may be decreased in time axis. As a matter of course, the schedule packet may be constructed so that one of the packet addressed to power saving communication apparatuses and the packet allocation domain addressed to the control apparatus of the power saving communication apparatuses may be decreased in time axis.

In addition, in the second embodiment, a description has been given of a case where an equal amount of electric power is required on transmitting and receiving operations. As a matter of course, the electric power consumption is effectively reduced even in a case where a different amount of electric power is required on transmitting and receiving operations.

As described so far, the second embodiment relates to a method for controlling communication between a control apparatus using an access control system, in which a packet allocation domain addressed to communication apparatuses and a packet allocation domain addressed to the control apparatus are scheduled two-dimensionally on a subchannel axis and a time axis to transmit a schedule packet periodically, and the communication apparatuses controlled by the control apparatus. Where the control apparatus is notified that three or more communication apparatuses are power saving communication apparatuses in the process of power saving operation, the control apparatus constructs a schedule packet, with the packet divided on the subchannel axis, so that packet allocation domains addressed to the power saving communication apparatuses and a packet allocation domain addressed to the control apparatus of the power saving communication apparatuses are decreased in time axis and also adjacent in time, thereby providing three or more power saving communication apparatuses which are capable of making adjacent in time the packet allocation domains addressed to the power saving communication apparatuses and the packet allocation domain of the control apparatus of the power saving communication apparatuses. (Third embodiment)

A description will be given of a third embodiment by reference to Fig. 6 and Fig. 9. In the third embodiment, a description will be given of operations of a communication system where the communication apparatuses 2a, 2b, 2c and 2d are power saving communication apparatuses and the communication apparatus 2a is low in remaining battery level. The communication apparatuses 2a, 2b, 2c and 2d transmit a packet indicating that they are power saving communication apparatuses when a communication line with the control apparatus 1 is opened. Further, the communication apparatus 2a transmits to the control apparatus 1 a low remaining battery level packet which is a packet indicating that a battery is low in remaining battery level when the battery is low in remaining battery level.

Fig. 6 is a functional block diagram of a control apparatus 1 in the third embodiment. As shown in Fig. 6, the control apparatus 1 is provided with a transmitter 150, a receiver 160, a transmission packet generator 119a1 , a packet content reading unit 119a2, a main control unit 111a1 , a power saving detector 111a2 and a low remaining battery level detector 111a3. The transmission packet generator 119a1 and the packet content reading unit 119a2 are a part of a wireless controller 119. The main control unit 111 a1 , the power saving detector 111a2 and the low remaining battery level detector 111a3 are a part of a CPU 111 a. The transmitter 150 and the receiver 160 are provided with a wireless module 120, an oscillator 121 , an antenna 123, and an antenna 124. In Fig. 6, the receiver 160 of the control apparatus 1 converts a received packet from an analog signal to a digital signal and delivers the converted packet to the packet content reading unit 119a2. The packet content reading unit 119a2 reads contents of the packet and delivers the contents of the packet which can be processed by the main IC 111 to the power saving detector 111 a2, the main control unit 111a1 and the low remaining battery level detector 111a3.

The power saving detector 111a2 makes a determination from the contents of the packet on whether the communication apparatus that transmits the packet is a power saving communication apparatus for each of the communication apparatuses and notifies the main control unit 111a1 of the determination result. The low remaining battery level detector 111a3 makes a determination from contents of the packet on whether the communication apparatus that transmits the packet is a low remaining battery level communication apparatus for each of the communication apparatuses and notifies the main control unit 111a1 of the determination result. The main control unit 111a1 makes a determination on whether or not the communication apparatus which opens a communication line is a power saving communication apparatus or it is a low remaining battery level communication apparatus, generates DL-MAP and UL-MAP by priority so that the low remaining battery level communication apparatus can be decreased in power-on time, thereby allowing the transmission packet generator 119a1 to generate a schedule packet. The transmitter 150 converts the schedule packet from a digital signal to an analog signal and transmits the packet to a wireless space.

The communication apparatuses 2a, 2b, 2c, 2d and 2e transmit and receive a packet at a timing which is scheduled within DL-MAP and UL-MAP of the schedule packet received from the control apparatus 1. Further, the communication apparatuses 2a, 2b, 2c and 2d, which are power saving communication apparatuses, perform a power saving operation by switching the power off at a timing other than that scheduled for them, thereby reducing the electric power consumption.

Specific allocations of UL bursts #a, #b, #c, #d and #e and those of DL bursts #a, #b, #c, #d and #e in the third embodiment will be described by reference to Fig. 9.

Fig. 9 is a frame configuration diagram of a communication system in the third embodiment. The time axis and subchannel axis of the frame are the same as those in the first embodiment and the second embodiment. Allocations of domains other than DL burst and UL burst to be allocated to each communication apparatus are also the same as those in the first embodiment and the second embodiment.

DL burst #a and UL burst #a addressed to the communication apparatus 2a are respectively decreased in time axis to the greatest extent because the communication apparatus 2a is a low remaining battery level communication apparatus. And, 192 slots of (subchannels 1 to 32) x (symbols 3 to 8) are allocated to DL burst #a and 90 slots of (subchannels 1 to 30) x (symbols 13 to 15) are allocated to UL burst #a so that DL burst #a and UL burst #a are adjacent in time. The communication apparatuses 2b, 2c and 2d which are power saving communication apparatuses but not low in remaining battery level are respectively allocated to include symbol 32 on Downlink subframe and symbol 1 on Uplink subframe so that DL burst #b and UL burst #b, DL burst #c and UL burst #c, and DL burst #d and UL burst #d are respectively adjacent in time. And, 180 slots of (subchannels 1 to 10) x (symbols 15 to 32) and 12 slots of (subchannel 11 ) x (symbols 20 to 32), a total of 192 slots, are allocated to DL burst #b, and 90 slots of (subchannels 1 to 10) x (symbols 1 to 9) are allocated to UL burst #b. 6 slots of (subchannel 11 ) x (symbols 15 to 32), 180 slots of (subchannels 12 to 21 ) x (symbols 15 to 32), and 6 slots of (subchannel 22) x (symbols 27 to 32), a total of 192 slots, are allocated to DL burst #c, and 90 slots of (subchannels 11 to 20) x (symbols 1 to 9) are allocated to UL burst #c. Then, 12 slots of (subchannel 22) x (symbols 15 to 26) and 180 slots of (subchannels 23 to 32) x (symbols 15 to 32), a total of 192 slots, are allocated to DL burst #d, and 90 slots of (subchannels 21 to 30) x (symbols 1 to 9) are allocated to UL burst #d. DL burst #e and UL burst #e addressed to the communication apparatus

2e are allocated to a remaining domain other than those allocated to the communication apparatus 2a, 2b, 2c and 2d. And, 192 slots of (subchannels 1 to 32) x (symbols 9 to 14) are allocated to DL burst #e, and 90 slots of (subchannels 1 to 30) x (symbols 10 to 12) are allocated to UL burst #e. A description will be given of the effect of reducing the electric power consumption of the communication apparatus 2a which is a low remaining battery level communication apparatus and the communication apparatuses 2b, 2c and 2d which are power saving communication apparatuses in the third embodiment. Time during which the communication apparatus 2a performs transmitting and receiving operations is 8 symbol times from symbol 1 to symbol 8 on Downlink subframe and 3 symbol times from symbol 13 to symbol 15 on Uplink subframe, a total of 11 symbol times. Further, since symbol 15 on Uplink subframe continues to symbol 1 on Downlink subframe of a subsequent frame across RTG, a total of 12 symbol times to which RTG is added is time during which the electric power is to be supplied to the communication apparatus 2a. In addition, symbol 12 on Uplink subframe, which is power-up time, requires the supply of electric power. More specifically, power saving time during which the electric power can be switched off is to be 36 symbol times, of 1 frame 49 symbol times. Therefore, it is possible to suppress the electric power consumption by 73.5%.

Time during which the communication apparatus 2b performs transmitting and receiving operations is 20 symbol times from symbols 1 , 2 and symbols 15 to 32 on Downlink subframe and 9 symbol times from symbol 1 to symbol 9 on Uplink subframe, a total of 29 symbol times. Further, since symbol 32 on Downlink subframe continues to symbol 1 on Uplink subframe across TTG, a total of 30 symbol times to which TTG is added is time during which the electric power is to be supplied to the communication apparatus 2b. In addition, since 2 symbol times of symbol 14 on Downlink subframe and RTG are required as power-up time, power saving time during which the electric power can be switched off is to be 17 symbol times, of 1 frame 49 symbol times. Therefore, it is possible to suppress the electric power consumption by 34.7%.

Since the communication apparatuses 2c and 2d are also equal in power saving time to the communication apparatus 2b, it is also possible to suppress the electric power consumption by 34.7%. As described so far, it is possible to suppress the electric power consumption of all of the communication apparatuses 2a, 2b, 2c and 2d, which are power saving communication apparatuses and also suppress by priority the electric power consumption of the communication apparatus 2a which is a low remaining battery level communication apparatus. In the third embodiment, a description was given of a case where one frame is to cover 32 subchannels on a subchannel axis, and on a time axis, in addition to 32 symbols with regard to Downlink subframe and 15 symbols with regard to Uplink subframe, 1 symbol time of TTG and that of RTG are included, and one frame time is to cover a total of 49 symbols. As a matter of course, any values are acceptable as these values.

Still further, in the third embodiment, a description has been given of a case where the number of slots of DownLink and the number of slots of UpLink are equally allocated to each of the five communication apparatuses. As a matter of course, any number of slots may be allocated to each of the communication apparatuses.

Still further, in the third embodiment, a description has been given of a case where an equal amount of electric power is required on transmitting and receiving operations. As a matter of course, the electric power consumption can be effectively reduced even in a case where a different amount of electric power is required on transmitting and receiving operations.

In addition, it is possible that upon receipt of a power saving request from two or more communication apparatuses, the control apparatus 1 checks a remaining battery level of each of the communication apparatuses and makes smaller the number of symbols on a time axis of a communication apparatus lower in remaining battery level than the number of symbols on the time axis of a communication apparatus greater in remaining battery level.

As described so far, in the third embodiment, where the control apparatus is notified that the power saving communication apparatus is a low remaining battery level communication apparatus low in remaining battery level, the control apparatus constructs a schedule packet so that a packet allocation domain of the low remaining battery level communication apparatus is decreased in time axis to a greater extent than packet allocation domains of other power saving communication apparatuses, a priority can be given to a decrease in power-on time of the low remaining battery level communication apparatus which is in particular required for reduction in electric power consumption among power saving communication apparatuses. It is, thereby, possible to suppress the electric power consumption of the low remaining battery level communication apparatus.

As described so far, the control apparatus 1 is provided with the receiver 160 for receiving a packet free of a power saving request or a packet containing the power saving request from the communication apparatuses 2a, 2b, 2c, 2d, 2e, the main control unit 111a for setting a transmission packet having a first time period where the receiver 160 receives the packet free of the power saving request and setting a transmission packet having a second time period shorter in time length than the first time period where the receiver 160 receives the packet containing the power saving request, and the transmitter 150 for transmitting a packet having the first time period set by the main control unit 111a or a packet having the second time period to the communication apparatuses 2a, 2b, 2c, 2d, 2e. Therefore, where the packet containing the power saving request is received from the communication apparatuses 2a, 2b, 2c, 2d, 2e, a time period of the packet transmitted to the communication apparatuses 2a, 2b, 2c, 2d, 2e is set to the second time period shorter in time length, thus making it possible to shorten the time necessary for activating the communication apparatuses 2a, 2b, 2c, 2d, 2e in the process of power saving request to receive the packet and also to suppress the electric power consumption of the communication apparatuses 2a, 2b, 2c, 2d, 2e.

Further, the main control unit 111a sets a transmitting schedule of a received packet addressed to the control apparatus 1 to be adjacent to a transmitting schedule of a transmission packet addressed to the communication apparatuses 2a, 2b, 2c, 2d, 2e. Therefore, time for transmitting the transmission packet from the control apparatus 1 to the communication apparatuses 2a, 2b, 2c, 2d, 2e is allowed to be continuous to time for transmitting the packet from the communication apparatuses to the control apparatus, and the communication apparatuses 2a, 2b, 2c, 2d, 2e are not required to switch the power supply off between packet receiving processing and packet transmitting processing. It is, therefore, possible to further reduce the electric power consumption of the communication apparatuses 2a, 2b, 2c, 2d, 2e.

It is noted that the CPU 111a, the EMAC 111c, the transmitter 150 and the receiver 160 may be formed as a single integrated circuit.

The circuit module 110 may also be formed as a single integrated circuit. Further, the frequency width may also mean size of numbers of subchannels.

Industrial Applicability

As described so far, the control apparatus, the communication apparatus, the communication method and the integrated circuit which are related to the implementation of the present invention are effectively usable in saving the electric power of a portable wireless communication apparatus used for mobile communications with a battery accumulator as a driving source and, in particular, appropriate for an application of a communication system where a wireless telephone device or a PDA often have difficulty in charging a battery low in remaining battery level is used as a communication apparatus.

Reference Signs List

1 : Control apparatus 2a, 2b, 2c, 2d, 2e: Communication apparatus

3a, 3b, 3c, 3d, 3e: Wireless communication channel

11 : Housing

12: Display unit

13: DC power supply connector 14: LAN modular jack

15: WAN modular jack

16: Electric power line

17: LAN cable

110: Circuit module 111 : Main IC

111 a: CPU

111a1 : Main control unit

111a2: Power saving detector

111 a3: Low remaining battery level detector 111 b: BCU

111 c, 111d: EMAC 111e: PCIU

111f: Main bus

111 g: Local bus

112: Oscillator 113: Reset IC

114: SDRAM

115: Flash ROM

116, 117: EPHY

118: DC-DC converter 119: Wireless controller

119a : MAC block

119a1 : Transmission packet generator

119a2: Packet content reading unit

119b : PHY block 120: Wireless module

120a, 120b: Transmitting-receiving switching SW

120c, 12Od: LNA

12Oe, 12Of: PA

12Og: RF modulator-demodulator 121 : Oscillator

150: Transmitter

160: Receiver

201 : Housing

202: LCD 203: Key matrix

204: Microphone

205: External antenna

206: Loud speaker

Claims

1. A control apparatus, comprising: a receiver which is adapted to receive from a communication apparatus 5 first data free of a power saving request or second data including the power saving request; a schedule setting unit which is adapted to set third data having a first time period in a case where the receiver receives the first data, and to set fourth data having a second time period shorter in time length than the first time period0 in a case where the receiver receives the second data; and a transmitter which is adapted to transmit to the communication apparatus the third data or the fourth data set by the schedule setting unit.

2. The control apparatus as set forth in claim 1 , 5 wherein the schedule setting unit sets a time period of fifth data to be received next time from the communication apparatus to a third time period in a case where the transmitter transmits the third data, and sets a time period of sixth data to be received next time from the communication apparatus to a fourth time period shorter in time length than the third time period in a case where the o transmitter transmits the fourth data.

3. The control apparatus as set forth in claim 1 or 2, wherein the schedule setting unit sets a first frequency width with respect to the third data in a case where the receiver receives the first data, and 5 sets a second frequency width greater in width than the first frequency width to the fourth data in a case where the receiver receives the second data.

4. The control apparatus as set forth in any one of claims 1 to 3, wherein the schedule setting unit sets a frequency width of fifth data to0 be received next time from the communication apparatus to a third frequency width in a case where the transmitter receives the third data, and sets a frequency width of sixth data to be received next time from the communication apparatus to a fourth frequency width greater in width than the third frequency width in a case where the transmitter transmits the fourth data. 5

5. The control apparatus as set forth in claim 4, wherein the schedule setting unit sets a schedule for transmitting the sixth data adjacent to a schedule for transmitting the fourth data.

6. The control apparatus as set forth in any one of claims 1 to 5, wherein the power saving request is information indicating a remaining battery level of the communication apparatus.

7. The control apparatus as set forth in claim 6, wherein the receiver receives seventh data including a power saving request from an other communication apparatus, wherein the transmitter transmits eighth data having a fifth time period to the other communication apparatus in a case where the receiver receives the seventh data, wherein the control apparatus further comprises a comparison unit which is adapted to compare first information contained in the second data to indicate a remaining battery level of the communication apparatus with second information contained in the seventh data to indicate a remaining battery level of the other communication apparatus, and wherein the schedule setting unit sets the second time period to be greater in time length than the fifth time period in a case where the first information is greater than the second information, and sets the second time period to be smaller in time length than the fifth time period in a case where the first information is smaller than the second information.

8. The control apparatus as set forth in claim 2, further comprising an assignment unit which is adapted to assign information indicating the first time period set by the schedule setting unit to the third data, and to assign information indicating the second time period set by the schedule setting unit to the fourth data.

9. A communication apparatus for receiving the first data transmitted from the control apparatus as claimed in claim 8, the communication apparatus comprising: a receiver which is adapted to receive one of the third data and the fourth data; and a setting unit which is adapted to set the third time period to the fifth data on the basis of information indicating the first time period upon receipt of the third data, and to set the fourth time period to the sixth data on the basis of information indicating the second time period upon receipt of the fourth data.

10. The communication apparatus as set forth in claim 9, further comprising: an assignment unit which is adapted to assign a power saving request to the second data to be transmitted to the control apparatus; and a transmitter which is adapted to transmit the second data to which the power saving request is assigned.

11. The communication apparatus as set forth in claim 10, further comprising: a battery for supplying electric power to the communication apparatus; and a remaining battery level detector which is adapted to detect a remaining battery level of the battery, wherein the assignment unit assigns information indicating the remaining battery level to the power saving request.

12. The control apparatus as set forth in claim 3 or 4, wherein each of the first to fourth frequency widths is expressed by number of subchannels.

13. A control apparatus, comprising: receiving means for receiving from a communication apparatus first data free of a power saving request or second data including the power saving request; schedule setting means for setting third data having a first time period in a case where the receiving means receives the first data, and setting fourth data having a second time period shorter in time length than the first time period in a case where the receiving means receives the second data; and transmitting means for transmitting to the communication apparatus the third data or the fourth data set by the schedule setting means.

14. The control apparatus as set forth in claim 13, wherein the schedule setting means sets a time period of fifth data to be received next time from the communication apparatus to a third time period in a case where the transmitting means transmits the third data, and sets a time period of sixth data to be received next time from the communication apparatus to a fourth time period shorter in time length than the third time period in a case where the transmitting means transmits the fourth data.

15. The control apparatus as set forth in claim 13 or 14, wherein the schedule setting means sets a first frequency width with respect to the third data in a case where the receiving means receives the first 0 data, and sets a second frequency width greater in width than the first frequency width to the fourth data in a case where the receiving means receives the second data.

16. The control apparatus as set forth in any one of claims 13 to 15,5 wherein the schedule setting means sets a frequency width of fifth data to be received next time from the communication apparatus to a third frequency width in a case where the transmitting means receives the third data, and sets a frequency width of sixth data to be received next time from the communication apparatus to a fourth frequency width greater in width than the third frequency o width in a case where the transmitting means transmits the fourth data.

17. The control apparatus as set forth in claim 16, wherein the schedule setting means sets a schedule for transmitting the sixth data adjacent to a schedule for transmitting the fourth data. 5

18. The control apparatus as set forth in any one of claims 13 to 17, wherein the power saving request is information indicating a remaining battery level of the communication apparatus.

0 19. The control apparatus as set forth in claim 18, wherein the receiving means receives seventh data including a power saving request from an other communication apparatus, wherein the transmitting means transmits eighth data having a fifth time period to the other communication apparatus in a case where the receiving5 means receives the seventh data, wherein the control apparatus further comprises comparison means for comparing first information contained in the second data to indicate a remaining battery level of the communication apparatus with second information contained in the seventh data to indicate a remaining battery level of the other communication apparatus, and wherein the schedule setting means sets the second time period to be greater in time length than the fifth time period in a case where the first information is greater than the second information, and sets the second time period to be smaller in time length than the fifth time period in a case where the first information is smaller than the second information.

20. The control apparatus as set forth in claim 14, further comprising assignment means for assigning information indicating the first time period set by the schedule setting means to the third data, and assigning information indicating the second time period set by the schedule setting means to the fourth data.

21. A communication apparatus for receiving the first data transmitted from the control apparatus as claimed in claim 20, the communication apparatus comprising: receiving means for receiving one of the third data and the fourth data; and setting means for setting the third time period to the fifth data on the basis of information indicating the first time period upon receipt of the third data, and setting the fourth time period to the sixth data on the basis of information indicating the second time period upon receipt of the fourth data.

22. The communication apparatus as set forth in claim 21 , further comprising: assignment means for assigning a power saving request to the second data to be transmitted to the control apparatus; and transmitting means for transmitting the second data to which the power saving request is assigned.

23. The communication apparatus as set forth in claim 22, further comprising: a battery for supplying electric power to the communication apparatus; and remaining battery level detecting means for detecting a remaining battery level of the battery, wherein the assignment means assigns information indicating the remaining battery level to the power saving request.

24. The control apparatus as set forth in claim 15 or 16, wherein each of the first to fourth frequency widths is expressed by number of subchannels.

25. A communication method, comprising: receiving from a communication apparatus first data free of a power saving request or second data including the power saving request; setting third data having a first time period in a case where the first data is received, and setting fourth data having a second time period shorter in time length than the first time period in a case where the second data is received; and transmitting to the communication apparatus the set third data or the set fourth data.

26. The communication method as set forth in claim 25, wherein a time period of fifth data to be received next time from the communication apparatus is set to a third time period in a case where the third data is transmitted, and a time period of sixth data to be received next time from the communication apparatus is set to a fourth time period shorter in time length than the third time period in a case where the fourth data is transmitted.

27. The communication method as set forth in claim 25 or 26, wherein a first frequency width with respect to the third data is set in a case where the first data is received, and a second frequency width greater in width than the first frequency width is set to the fourth data in a case where the second data is received.

28. The communication method as set forth in any one of claims 25 to 27, wherein a frequency width of fifth data to be received next time from the communication apparatus is set to a third frequency width in a case where the third data is transmitted, and a frequency width of sixth data to be received next time from the communication apparatus is set to a fourth frequency width greater in width than the third frequency width in a case where the fourth data is transmitted.

29. The communication method as set forth in claim 28, wherein a schedule for transmitting the sixth data is set adjacent to a schedule for transmitting the fourth data.

30. The communication method as set forth in any one of claims 25 to 29, wherein the power saving request is information indicating a remaining battery level of the communication apparatus.

31. The communication method as set forth in claim 30, comprising: receiving seventh data including a power saving request from an other communication apparatus; transmitting eighth data having a fifth time period to the other communication apparatus in a case where the seventh data is received; comparing first information contained in the second data to indicate a remaining battery level of the communication apparatus with second information contained in the seventh data to indicate a remaining battery level of the other communication apparatus; and setting the second time period to be greater in time length than the fifth time period in a case where the first information is greater than the second information, and setting the second time period to be smaller in time length than the fifth time period in a case where the first information is smaller than the second information.

32. The communication method as set forth in claim 28, further comprising assigning information indicating the first time period to the third data, and assigning information indicating the second time period to the fourth data.

33. The communication method as set forth in claim 27 or 28, wherein each of the first to fourth frequency widths is expressed by number of subchannels.

34. An integrated circuit, comprising: a receiver which is adapted to receive from a communication apparatus first data free of a power saving request or second data including the power saving request; a schedule setting unit which is adapted to set third data having a first time period in a case where the receiver receives the first data, and to set fourth data having a second time period shorter in time length than the first time period in a case where the receiver receives the second data; and a transmitter which is adapted to transmit to the communication apparatus the third data or the fourth data set by the schedule setting unit.