Methods and apparatus for retransmission based access priority in a communications system

DETAILED DESCRIPTION The present invention provides methods and apparatus for providing access priority in a MAC protocol of a communications system such as, for example, with respect to UMTS RACH.
Particularly, the invention introduces several access priority methodologies including: (i) random chip delay access priority (RCDAP); (ii) random backoff based access priority (RBBAP); (iii) variable logical channel based access priority (VLCAP); (iv) a UMTS-specific variation to the variable logical channel based access priority scheme (VLCAP'); (v) probability based access priority (PBAP); and (vi) retransmission based access priority (REBAP).
In one aspect of the invention, RCDAP methods and apparatus are provided.
In RCDAP, each priority class is advantageously assigned a different chip delay from among chip delay distributions prior to submitting an access request to the base station.
Preferably, those classes with a higher priority are given a smaller average random chip delay such that their access requests will have a higher probability of being captured compared to those submitted by users with a lower priority class.
In another aspect of the invention, RBBAP methods and apparatus are provided.
In RBBAP, each priority class is advantageously assigned a different backoff delay.
Preferably, requests associated with higher access priority will have a smaller average backoff delay.
Whenever there is a collision or some other reason an access request is not successfully received at the base station, the remote terminal, depending on the class i, chooses a random delay distributed between a pre-determined range.
In yet another aspect of the invention, VLCAP methods and apparatus are provided.
In VLCAP, each subscriber is given an access priority class i.
Preferably, those with the highest priority can access all the logical access channel for which the base station is configured, while those with lowest priority are only allowed to access a small subset of logical access channels, e.
g.
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