Radio communication system

Abstract

A radio communication system has a random access channel for the transmission of data ( 214 ) from a secondary station to a primary station. Such a channel is intended for use by secondary stations having packets of data ( 214 ) to transmit to a primary station while not actually engaged in a call. A problem with known systems of this type is that a secondary station requesting access also specifies which of a plurality of channels it wishes to access. If that channel is busy access is denied, even if other suitable channels are available. In the present system the primary station transmits a random access channel availability (AV) message ( 302 ) once per frame to inform secondary stations about the resources currently available. Hence a secondary station can select a channel known to be free. If no channels are available the secondary station can avoid a wasted access attempt.

1 - 14 . (canceled) 
     
     
         15 . A primary station, comprising:
 a transmitter that is configured to transmit a random access channel status message to a plurality of secondary stations, and   a controller that is configured to:
 determine an availability of each of a plurality of random access channels, 
 determine a highest available date rate for each available channel of the plurality of random access channels, and 
 create the random access status message that includes an indicated highest available data rate for each of the plurality of random access channels, 
   
     
     
         16 . The primary station of  claim 15 , wherein the random access channel status message is transmitted by said primary station as a part of a paging indicator channel. 
     
     
         17 . The primary station of  claim 15 , wherein the random access channel status message is transmitted by said primary station as a part of an acquisition indicator channel. 
     
     
         18 . The primary station of  claim 15 , wherein the indicated highest available data rate serves to identify whether the corresponding random access channel is available, and identifies a highest available data rate for available channels of the plurality of random access channels. 
     
     
         19 . The primary station of  claim 15 , wherein the indicated highest available data rate of at least one available random access channel is lower than a highest data rate that could be made available to the at least one random access channel, based on a potential future demand for capacity.