WIRELESS COMMUNICATION DEVICE AND WIRELESS COMMUNICATION METHOD

• US 20090040991A1
• Filed: 08/08/2008
• Published: 02/12/2009
• Est. Priority Date: 08/08/2007
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Yamada, Akira, IGARASHI, Kei
• Granted Patent: US 8,144,677 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 65/1059 End-user terminal functionalities specially adapted for real-time communication
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04W 28/20 Negotiating bandwidth
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An object of the present invention is to realize a distributed autonomous transmission scheduling by using a terminal without the need to observe packets in relation to communication of other wireless terminals in a cell, such as VoIP, in which a plurality of wireless terminals that periodically transmit packets exist, thereby allowing intermittent reception during the packet observation and enabling to control power consumption of the wireless terminal as well as to reduce the load to thereby improve the communication quality. To attain the object, a VoIP terminal 100 recognizes and retains a scheduling table received by a wireless terminal that is connected to a wireless base station and that is not communicating with other wireless terminals, additionally writes terminal information of the terminal in the scheduling table at the start of communication of the terminal, and broadcasts the scheduling table. The scheduling table is updated when an update time of another scheduling table received by a terminal in communication which is newer than an update time of the scheduling table and different from the order of transmission, and an exclusive or preferential bandwidth available period is set for communication in accordance with the scheduling table.

Claims

1. A wireless communication device that transmits and receives packets based on a packet transmission system for allocating a radio bandwidth by a virtual carrier sensing, the wireless communication device comprising:

a first transmitting means for periodically or occasionally transmitting a scheduling table, wherein a transmission order written by at least one of a plurality of wireless communication devices, to a wireless base station;

a recognizing and retaining means for recognizing and retaining a scheduling table received when the wireless communication device is connected to the wireless base station and is not communicating with other wireless communication device;

a second transmitting means for additionally writing information of the wireless communication device to the scheduling table which is retained by the recognizing and retaining means at the beginning of communication and for transmitting the additionally-written scheduling table at least once;

an updating means for updating the retained scheduling table, when an update time of another scheduling table received from the wireless base station is later than an update time of the retained scheduling table and another transmission order received from the wireless base station is different from the transmission order in the retained scheduling table; and

a third transmitting means for communicating after setting an exclusive or preferential bandwidth available period in accordance with the scheduling table updated by the updating means.

2. The wireless communication device according to claim 1, wherein:

the updating means deletes the information of the wireless communication device from the retained scheduling table immediately before transition to a state of being connected only to the wireless base station or immediately after an end of communication, after at least one of the plurality of wireless communication devices that has been in communication ends the communication in accordance with the scheduling table; and

the third transmitting means transmits the scheduling table from which the information is deleted, at least once.

3. The wireless communication device according to claim 1, wherein:

the updating means deletes the information of the own wireless communication device from the scheduling table when at least one of the plurality of wireless communication devices in communication moves, while a communication state being maintained, from a cell which is a current communication area of the wireless base station to another cell having another wireless base station in accordance with the scheduling table; and

the third transmitting means transmits the scheduling table from which the information is deleted, to the wireless base station at least once.

4. The wireless communication device according to claim 3, wherein:

the first transmitting means communicates with a random accessing by the virtual carrier sensing for a predetermined time, after the wireless communication device moves to another cell; and

the second transmitting means additionally writes the information of the wireless communication device in the scheduling table received from another wireless communication device while random accessing after the wireless communication device moves to another cell and transmits the additionally-written scheduling table to the wireless base station at least once.

5. The wireless communication device according to claim 1, wherein a transmission valid period that becomes invalid after a lapse of a predetermined period which is written in the retained scheduling table.

6. A wireless communication method for transmitting and receiving packets based on a packet transmission system for allocating a radio bandwidth by virtual carrier sensing, the wireless communication method comprising:

a first step for periodically or occasionally transmitting a scheduling table, wherein a transmission order written by at least one of a plurality of wireless communication devices, to a wireless base station;

a second step for recognizing and retaining a scheduling table received when the wireless communication device is connected to the wireless base station and is not communicating with other wireless communication device;

a third step for additionally writing information of the wireless communication device to the scheduling table which is retained by the recognizing and retaining means at the beginning of communication and for transmitting the additionally-written scheduling table at least once;

a fourth step for updating the retained scheduling table, when an update time of another scheduling table received from the wireless base station is later than an update time of the retained scheduling table and another transmission order received from the wireless base station is different from the transmission order in the retained scheduling table; and

a fifth step for communicating after setting an exclusive or preferential bandwidth available period in accordance with the scheduling table updated at the fourth step.