Group randomly addressed polling MAC protocol for wireless data

• US 5,436,905 A
• Filed: 05/16/1994
• Issued: 07/25/1995
• Est. Priority Date: 05/16/1994
• Status: Expired due to Fees

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Chen, Kwang-Cheng, Li, Meng-Che
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): BLUM, RUSSELL
• Application Number:
  US08/243,200
• Time in Patent Office: 435 Days
• Field of Search: 370/95.2, 370/95.1, 379/58, 379/59, 379/60, 455/33.1, 455/33.2, 455/54.1, 455/54.2, 340/825.08
• US Class Current: 370/346
• CPC Class Codes: H04L 12/423 with centralised control, e.g. polling
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A method to provide improved medium access control (MAC) protocol for a wireless local area network (LAN) comprising the steps of: (a) pre-arranging a polling cycle to be broadcast from the base station into a sequence of broadcast groups, (b) assigning each active mobile node to a randomly chosen broadcast group, (c) performing a group randomly addressed polling for each of the broadcast groups, and (d) assigning uncollided mobile nodes to their original randomly chosen broadcast group address. The uncollided mobile nodes will also be given the privilege of keeping their random numbers as fixed random numbers, until they collide with other mobile node(s) in subsequent polling cycle(s). All the collided mobile nodes, all newly active mobiles, and all newly joined mobile nodes are subject to a new polling cycle. The method has shown to provide excellent throughput (better than 0.90), stable convergence, and excellent delay behavior.

Claims

1. In a wireless local area network comprising a base station and a plurality of mobile nodes, a method to provide a medium access control protocol, said method comprising the following steps:

(a) pre-arranging a polling cycle to be broadcast from said base station into a sequence of Q broadcast groups, identified as groups 0 through Q-1, wherein Q is an integer, each broadcast group being considered as a sub-polling cycle;

(b) for those mobile nodes that have not been assigned to a fixed group address, assigning each mobile node intending to send at least a packet of data to said base station to a randomly chosen broadcast group I, wherein I is an integer from 0 to Q-1;

(c) starting from broadcast group 0 through broadcast group Q-1, performing a group randomly addressed polling as follows;

within each broadcast group I, performing a randomly addressed polling procedure comprising the following steps;

(i) broadcasting a first broadcast message from the base station to all mobile nodes under its coverage to signal a ready to receive at the base station from mobile node assigned to broadcast group I;

(ii) for those mobile nodes that have not been assigned a fixed random number, generating a first random number R in each mobile node belonging to broadcast group I, said first random number being selected from a set of numbers ranging from 0 to P-1, wherein P is an integer greater than or equal to Q;

(iii) simultaneously transmitting said first random numbers Rs from all active mobile nodes belonging to said broadcast group I to said base station;

(iv) collecting said first random numbers Rs at said base station and separating said mobile nodes into collided nodes and uncollided nodes, collided nodes being defined as those active nodes that transmitted a common random number with at least another node;

(v) transmitting said at least one packet of data from each of said uncollided mobile nodes to said base station;

(vi) assigning each of said uncollided mobile nodes to a fixed group address, each of said uncollided mobile nodes also being assigned a fixed random number which is its originally transmitted random number;

(vii) repeating steps (c)(i) through (c)(vii) for all the broadcast groups;

d) assigning each of said collided mobile nodes from previous step and all newly active mobile nodes, except those that have been assigned to a fixed group address, to a randomly chosen broadcast group;

(e) performing a group randomly addressed polling by repeating steps (c)(i) through (c)(vii) for all said broadcast groups; and

(f) repeating steps (d) and (e) if there exist collided and/or newly active mobile nodes.

2. The method to provide a medium access control protocol for a local area network according to claim 1, wherein said number of groups Q is a variable which is subject to change from one polling cycle to another.

3. The method to provide a medium access control protocol for a local area network according to claim 1, wherein said packet of data contains time-bounded data.

4. The method to provide a medium access control protocol for a local area network according to claim 1, wherein said mobile node transmits at least two of said first random numbers in step (c)(ii).

5. The method to provide a medium access control protocol for a local area network according to claim 1, wherein said local area network comprises at least ten mobile nodes and said first random numbers are selected from a group of integers from 0 to less than 5.

6. The method to provide a medium access control protocol for a local area network according to claim 1, wherein said local area network comprises at least twenty mobile nodes and said first random numbers are selected from a group of integers from 0 to less than 6.

7. The method to provide a medium access control protocol for a local area network according to claim 1, wherein said local area network comprises at least thirty mobile nodes and said first random numbers are selected from a group of integers from 0 to 6.