Collision avoidance technique for a multiple access radio communication system

• US 6,680,950 B1
• Filed: 12/23/1999
• Issued: 01/20/2004
• Est. Priority Date: 12/24/1998
• Status: Expired due to Term

• Current Assignee: NEC Personal Computers, Ltd.
• Original Assignee: NEC Corporation
• Inventors: Tada, Tetsunori, Nagata, Masahiro
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US09/471,607
• Time in Patent Office: 1,489 Days
• Field of Search: 370/338, 370/445, 370/447, 370/448, 370/461, 370/462, 370/348, 370/347, 455/450, 455/452, 455/453-455, 455/500, 455/510, 455/515
• US Class Current: 370/461
• CPC Class Codes: H04W 74/0816 with collision avoidance

Abstract

A radio base station, when detecting a collision of reception signals, transmits an access-restricted transmission allow signal IDLE2 to a irrelevant-to-collision radio terminal PS3 for access restriction. A plurality of relevant-to-collision radio terminals PS1 and PS2, when receiving the access-restricted transmission allow signal, set transmission delay times TR1 and TR2 determined by random numbers, respectively, and when receiving the access-restricted transmission allow signal after the lapse of their respective delay times, start the same transmission operation as when receiving a normal transmission allow signal. A separate radio terminal PS3, when receiving the access-restricted transmission allow signal before intended new signal transmission, suspends the new signal transmission until receiving the normal transmission allow signal.

Claims

1. A multiple access method in a radio communication system, which includes a system for random access control in response to collision detection and permits multiple accessing of a first radio station by a plurality of second radio stations, said method comprising steps of:

detecting a collision of signals received at said first radio station;

transmitting an access restricted transmission allow signal from said first radio station to second radio stations which are irrelevant to said collision of signals detected in said detecting step;

setting, responsive to said access restricted transmission allow signal, access restriction in said second radio stations which are irrelevant to said collision detected in said detecting step; and

resetting access restriction in said second radio stations which are irrelevant to said collision detected in said detecting step responsive to reception of a normal transmission allow signal at a said second radio station.

2. The multiple access method according to claim 1, wherein an irrelevant-to-collision second radio station, receiving the access-restricted transmission allow signal before intended new signal transmission, suspends the execution of the new signal transmission until receiving a normal transmission allow signal from the first radio station.

3. The multiple access method according to claim 2, a plurality of relevant-to-collision second radio stations, when receiving the access-restricted transmission allow signal after the lapse of a transmission delay time set at the time of collision occurrence, start a normal transmission operation corresponding to a transmission operation as when receiving a normal transmission allow signal.

4. A multiple access method in a radio communication system comprising a radio base station for detecting a collision of reception signal and a plurality of radio terminals, said method comprising the steps of:

detecting a collision of signals received at said radio base station;

transmitting an access restricted transmission allow signal from said radio base station to irrelevant-to-collision radio terminals;

setting, responsive to said access restricted transmission allow signal, a transmission delay time determined by a random number;

restarting a normal transmission operation, after the laps of the transmission delay time, that is responsive to receiving the access restricted transmission allow signal; and

suspension the execution of the new signal transmission by said irrelevant to collision radio terminal until receiving the normal transmission allow signal, when receiving the access restricted transmission allow signal before starting new signal transmission.

5. A multiple access method in a cordless telephone system comprising a provisional master terminal constituted by a slave terminal having a function of detecting a collision of reception signals and a plurality of slave terminals and capable of allowing iter-slave terminal communication, said method comprising steps of:

detecting a collision of signals received at said provisional master terminal;

transmitting an access restricted transmission allow signal from said provisional master terminal to irrelevant to collision slave terminals;

setting, responsive to said access restricted transmission allow signal, a transmission delay time determined by a random number access restricted transmission in said slave terminals which are irrelevant to said collision detected in said detecting step, and

suspending a new signal transmission until receiving the normal transmission access restriction allow signal in said slave terminals which are irrelevant to said collision detected in said detecting step.