Patent ID: 6785249
Filing Date: 2004-08-31
Classification: H04W

Abstract:
A method of detecting link imbalances in a digital cellular communication system comprising a plurality of wireless units and a plurality of base stations, wherein transmissions from the base stations to the wireless units are made using forward radio communication links and wherein transmissions from the wireless units to the base stations are made using reverse radio communication links, and wherein each forward link includes control and forward traffic channels, and each reverse link includes control and reverse traffic channels, the method comprising the steps of:detecting a link failure in a first radio communication link between a wireless unit and a first base station during a call initiation, the step of detecting the link failure comprising the step of determining whether the failure in the first radio communication link comprises a reverse link failure or a forward link failure: determining whether the link failure is due to a link imbalance in the first radio communication link; instructing the wireless unit to switch to a second radio communication link if the link imbalance exists; determining if the reverse link failure is due to a weak reverse link, the step of determining if the reverse link failed due to a weak reverse link comprising the step of determining whether a maximum number of access probes has been transmitted by the wireless unit to the first base station, wherein a value for the maximum number of access probes is transmitted in an access parameters message which is sent by the first base station to the wireless unit over a control channel associated with a forward link of the first base station; initiating by the wireless unit communication on a secondary communication system if the maximum number of access probes has been transmitted by the wireless unit to the first base station; and entering by the wireless unit an idle state and then re-initiate communication with a primary digital cellular communication system if the maximum number of access probes has not been transmitted by the wireless unit to the first base station.