Communication system, communication apparatus and communication method, and computer program

Abstract

To suitably suppress distribution delay at the time of multi-hop communication or broadcast transfer while including a communication station in a power-saving state. First, STA-A immediately transmits broadcast data to STA-B which is running in an active mode, and subsequentially, executes transmission of a beacon at a TBTT when STA-C operates a receiver, and then transmits the broadcast data to the STA-C. Thus, the broadcast data can be distributed to the STA-B which is running in the active mode with the minimum delay, and on the other hand, the broadcast data is distributed to the STA-C which is running in a sleep mode in a sure manner while generating a delay quantity of only T0.

The invention claimed is: 
     
       1. A communication system characterized in being made up of a plurality of communication stations which operate in an autonomous distributed manner,
 wherein at least a part of the communication stations are power-saving communication stations which operate in a sleep mode where a transmitter and a receiver of the power-saving communication stations are operated in an intermittent manner, and at least a part of the other communication stations are power-saving assistance stations having capabilities to trigger a period when the power-saving communication stations are awake by sending a message to the power-saving communication stations when the power-saving communication stations are in the sleep mode and capabilities to communicate with said power-saving communication stations: and 
 wherein at least a part of said power-saving assistance stations have a tow-delay broadcast low-delay data distribution function to execute data transmission each time each of the communication stations station serving as a transmission destination enters into an active state for activating the receiver, at the time of broadcast data distribution, such that the data transmission is performed immediately to a first one of communication stations that is awake and is performed to a second one of the communication stations that is in the sleep mode once the second one of the communication stations become awake. 
 
     
     
       2. The communication system according to  claim 1 , characterized in comprising:
 meanscircuitry in each of the communication stations configured to mutually notify other communication stations of communication station attributes regarding whether or not each respective communication station is a power-saving communication station, whether or not each respective communication station is a power-saving assistance station, or whether or not each respective communication station has the broadcast low-delay data distribution function. 
 
     
     
       3. The communication system according to  claim 2 , characterized in being the wherein communication stations which have notified other communication stations of the communication station attributes mutually determining determine whether to enter into a communication state based on matching results of between the mutual communication station attributes of the communication stations. 
     
     
       4. The communication system according to  claim 3 , characterized in the power-saving communication stations selecting not to enter into a communication state with a communication station which is not a power-saving assistance station, or the communication stations which are not a power-saving assistance station selecting not to enter into a communication state with a power-saving communication station. 
     
     
       5. The communication system according to  claim 3 , characterized in the power-saving communication stations selecting whether to enter into a communication state with a power-saving assistance station having no broadcast low-delay data distribution function while taking into consideration restrictions relating to distribution delay imposed on the communication system. 
     
     
       6. A communication apparatus which executes data communication under a communication environment made up of with a plurality of communication stations which operate in an autonomous distributed manner, characterized in comprising:
 communication means configured to execute transmission/reception with said communication environment; 
 communication control means configured to control a communication operation by said communication means; 
 a buffer configured for storm data;  
 power-saving assistance means circuitry configured to recognize that each adjacent to trigger a period when another communication station operates in a sleep mode for operating a transmitter and a receiver in an intermittent manner is awake by sending message to the another communication station when the another communication station is in the sleep mode; and 
 a low-delay broadcast distribution meanstransmitter configured to execute data transmission each time eachof the stored data communication station serving as a transmission destination enters into an active state for activating the receiver at the time of executing broadcast data distribution as to the plurality of communication stationseach time when the another communication station is awake, such that the data transmission is performed immediately to the another communication station in response to a determination that the another communication station is awake and is performed to the another communication station once the another communication station becomes awake in response to a determination that the another communication station is in the sleep mode. 
 
     
     
       7. The communication apparatus according to  claim 6 , characterized in further comprising:
 notifying meanscircuitry configured to mutually notify an adjacent communication station of communication station attributes of the communication apparatus regarding whether or not the self station communication apparatus operates in the sleep mode for operating the transmitter and the receiver of the communication apparatus intermittently, whether or not the self station communication apparatus includes said power-saving assistance means circuitry, or whether or not the self station communication apparatus includes the low-delay broadcast distribution meanstransmitter. 
 
     
     
       8. The communication apparatus according to claim  6  7, characterized in said communication control means determining further comprising circuitry configured to determine whether to enter into a communication state with each adjacent communication station based on matching results of between the mutual communication station attributes of each adjacent communication station and the communication apparatus. 
     
     
       9. A communication apparatus characterized in executing data communication under a communication environment made up of with a plurality of communication stations which operate in an autonomous distributed manner, comprising:
 circuitry  communication means configured to execute transmission/reception with said plurality of communication environment stations;   communication control means configured to control a communication operation by said communication means circuitry; and   notifying means configured to mutually notify an adjacent communication station of communication station attributes of the communication apparatus regarding whether or not the self station communication apparatus is a power-saving communication station which operates in a sleep mode for operating the transmitter and the receiver of said communication means circuitry intermittently, whether or not the self station  communication apparatus is a power-saving assistance station which can handle data communication with a communication station which operates in a sleep mode, or and whether or not the self station communication apparatus has a broadcast low-delay data distribution function for executing data transmission each time each communication station serving as a transmission destination to another communication apparatus each time the another communication apparatus enters into an active state for activating the receiver;   
 wherein said communication control means determine circuitry determines whether to enter into a communication state with each adjacent communication station based on matching results of between the mutual communication station attributes of the communication apparatus and communication station attributes of each adjacent communication station, such that the data transmission is performed immediately to a first adjacent communication station that is awake and is performed to a second adjacent communication station that is in the sleep mode once the second adjacent communication station become awake. 
 
     
     
       10. The communication apparatus according to  claim 9 , characterized in said communication control means determining wherein the circuitry determines to enter into a communication state with a communication station having said broadcast low-delay data distribution function at the time of the self station when the communication apparatus is operating in the sleep mode. 
     
     
       11. The communication apparatus according to  claim 10 , characterized in said communication control means determining wherein the circuitry determines to enter into a communication state with a communication station not having said broadcast low-delay data distribution function when restrictions are not imposed on broadcast data delay under said communication environment. 
     
     
       12. A communication method characterized in being arranged performed by a communication apparatus to execute data communication under a communication environment made up of with a plurality of communication stations which operate in an autonomous distributed manner, comprising:
 storing data;  
 a power-saving assistance step arranged to recognize that each adjacenttrigger period when another communication station operates in a sleep mode for operating a transmitter and a receiver intermittentlyis awake by sending a message to the another communication station when the another communication station is in the sleep mode; and 
 a low-delay broadcast distribution step arranged to executeexecuting data transmission of the stored data to the another communication station each time eachthe another communication station serving as a transmission destination enters into an active state for activating the receiver at the time of executing broadcast data distribution as to the plurality of communication stationsis awake, such that the data transmission is performed immediately to the another communication station in response to a determination that the another communication station is awake and is performed to the another communication station once the another communication station becomes awake in response to a determination that the another communication station is asleep. 
 
     
     
       13. A communication method characterized in being arranged to execute data communication under a communication environment made up of with a plurality of communication stations which operate in an autonomous distributed manner, comprising:
 a notifying step arranged to mutually notifynotifying, by a communication station, an adjacent communication station of communication station attributes of the communication apparatus regarding whether or not the self stationcommunication apparatus is a power-saving communication station which operates in the sleep modefor operating a transmitter and a receiver intermittently, whether or not the self stationcommunication apparatus is a power-saving assistance station which can handle data communication with a communication station which operates in a sleep mode, orand whether or not the self stationcommunication apparatus has a broadcastlow-delay data distribution function for executing data transmission each time each communication station serving as a transmission destinationto another communication apparatus each time the another communication apparatusenters into an active statefor activating the receiver; and 
 a determining step arranged to determine whether to enter into a communication state with each adjacent communication station based on matching results of between the mutual communication station attributes of the communication apparatus and communication station attributes of each adjacent communication station at the time the self station  communication station operating in the sleep mode; 
 wherein, in said determiningstep, determination is made to enter into a communication state with a communication station having said broadcast low-delay data distribution function, and also to enter into a communication state with a communication station not having said broadcast low-delay data distribution function when restrictions are not imposed on broadcast data delayunder the communication environment, such that the data transmission is performed immediately to a first one of the communication stations that is awake and is performed to a second one of the communication stations that is in the sleep mode once the second one of the communication stations become awake. 
 
     
     
       14. A computer program characterized in being described in a computer-readable format store in a non-transitory computer readable medium so as to execute processing for executing data communication on a computer under a communication environment made up of with a plurality of communication stations which operate in an autonomous distributed manner, causing said computer to execute:
 storing data;  
 a power-saving assistance step arranged to recognize that each adjacenttrigger a period when another communication station operates in a sleep mode for operating a transmitter and a receiver intermittentlyis awake by sending a message to the another communication station when the another communication station is in the sleep mode; and 
 a low-delay broadcast distribution procedure arranged to executeexecuting data transmission each time eachof the stored data to the another communication station each time the anothercommunication station serving as a transmission destination enters into an active state for activating the receiver at the time of executing broadcast data. distribution as to the plurality of communication stationsis awake, such that the data transmission is performed immediately to the another communication station in response to a determination that the another communication station is awake and is performed to the another communication station once the another communication station becomes awake in response to a determination that the another communication station is in the sleep mode. 
 
     
     
       15. A computer program characterized in being described in a computer-readable format store stored in a non-transitory computer readable medium so as to execute processing for executing data communication on a computer under communication environment made up of with a plurality of communication stations which operate in an autonomous distributed manner, causing said computer to execute:
 a notifying procedure arranged to mutually notifynotifying, by a communication apparatus, an adjacent communication station of communication station attributes of the communication apparatus regarding whether or not the self stationcommunication apparatus is a power-saving communication station which operates in the sleep modefor operating a transmitter and a receiver intermittently, whether or not the self stationcommunication apparatus is a power-saving assistance station which can handle data communication with a communication station which operates in a sleep mode, orand whether or not the self stationcommunication apparatus has a broadcastlow-delay data distribution function for executing data transmission to another communication apparatus each time each communication station serving as a transmission destinationwhen the another communication apparatus enters into an active statefor activating the receiver; and 
 a determining step arranged to determine whether to enter into a communication state with each adjacent communication station based on matching results of between the mutual communication station attributes of the communication apparatus and communication station attributes of each adjacent communication station at the time the self station communication apparatus operating in the sleep mode; 
 wherein, in said determining step, determination is made to enter into a communication state with a communication station having said broadcast low-delay data distribution function, and also to enter into a communication state with a communication station not having said broadcast  low-delay data distribution function when restrictions are not imposed on broadcast data delayunder the communication environment, such that the data transmission is performed immediately to a first one of communication stations that is awake and is performed to a second one of the communication stations that is in the sleep mode once the second one of the communication stations become awake.