Wireless communication terminal and wireless communication method

• US 8,149,864 B2
• Filed: 02/19/2010
• Issued: 04/03/2012
• Est. Priority Date: 02/28/2006
• Status: Expired due to Fees

• 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, Sugiyama, Takatoshi
• Primary Examiner(s): Moe, Aung S
• Assistant Examiner(s): LOUIS, VINNCELAS
• Application Number:
  US12/709,055
• Publication Number:
  US 20100150074A1
• Time in Patent Office: 774 Days
• Field of Search: 370328-329, 370/338, 370/455, 370/453, 370/241, 370/503, 714/11, 455/450, 709/223, 713/375, 348/537
• US Class Current: 370/445
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A communication terminal used in a mobile communication system complying with a carrier sense multiple access scheme is disclosed. The communication terminal includes: a receiving unit configured to receive a wireless packet transmitted by another communication terminal or a base station; a determination unit configured to determine periodic transmission timing of the communication terminal based on determination criterion information included in the wireless packet; and a transmission unit configured to periodically transmit wireless packets to the base station based on the transmission timing.

Claims

1. A communication terminal used in a mobile communication system complying with a carrier sense multiple access scheme and including a plurality of communication terminals that transmit wireless packets according to a same periodicity based on a respective different timing, the communication terminal comprising:

a receiving unit configured to receive a wireless packet transmitted by another communication terminal or a base station;

a determination unit configured to compare a received signal quality included in the wireless packet that is reported to the base station by the another communication terminal with a received signal quality of the communication terminal so as to determine a transmission timing of the communication terminal based on the result of the comparison;

a transmission unit configured to periodically transmit wireless packets to the base station based on the transmission timing; and

a re-synchronization request transmission unit configured to transmit a re-synchronization signal to other communication terminals when a packet error rat e exceeds a predetermined value, wherein each communication terminal of the other communication terminals that receives the re-synchronization signal compares a received signal quality included in a packet transmitted by another communication terminal with a received signal quality of the communication terminal that receives the re-synchronization signal so as to re-determine a transmission timing of the communication terminal that receives the re-synchronization signal based on the result of the comparison, and

wherein the determination unit re-determines the transmission timing when receiving a re-synchronization signal from another communication terminal.

2. A communication method used on a communication terminal in a mobile communication system complying with a carrier sense multiple access scheme and including a plurality of communication terminals that transmit wireless packets according to a same periodicity based on a respective different timing, the method comprising:

receiving, at the communication terminal, a wireless packet transmitted by another communication terminal or a base station;

comparing, at the communication terminal, a received signal quality included in the wireless packet that is reported to the base station by the another communication terminal with a received signal quality of the communication terminal so as to determine a transmission timing of the communication terminal based on the result of the comparison;

periodically transmitting, at the communication terminal, wireless packets to the base station based on the transmission timing;

transmitting, at the communication terminal, a re-synchronization signal to other communication terminals when a packet error rate exceeds a predetermined value, wherein each communication terminal of the other communication terminals that receives the re-synchronization signal compares a received signal quality included in a packet transmitted by another communication terminal with a received signal quality of the communication terminal that receives the re-synchronization signal so as to re-determine a transmission timing of the communication terminal that receives the re-synchronization signal based on the result of the comparison; and

re-determining, at the communication terminal, the transmission timing when receiving a re-synchronization signal from another communication terminal.