Motorola Corporation

John R Haug

Phillip D Rasky

David E Borth

Eric R Schorman

Walter J Rozanski, Jr

Charles N Lynk

Kenneth A Felix

Gregory M Chiasson

John S Csapo

Morton Stern

Philip J Smanski

Richard A Kaman

The dual mode communication network comprises a first communication system having a frame structure and a first traffic channel protocol and a second communication system having the frame structure and a second traffic channel protocol. In the network, only one of the first and second traffic channel protocols supports forward error correction coding.

Dual mode communication network

Registration operates by sensing (106) the availability of a first communication system. A quality factor of a channel of the system is measured (111). A channel of the first system is selected if the quality factor of the channel exceeds a threshold (113). If selected, the subscriber attempts to register the call (114). If the registration fails, the availability of a second communication system is sensed (107). A quality factor of a channel of the second system is measured (111) and selected (113), if the quality factor exceeds a threshold. The subscriber will then attempt to register (114) with the second system. Reassignment operates by determining if the first system has reached a capacity limit (126). If it has, it determines if a channel on the second system is available (128). If available, a transfer of the call from the first to the second system will be attempted (132).

Method of registering/-reassigning a call in a dual mode communication

A dual mode radio communication unit for a digital communication system is provided having an error controller including an error detection encoder and a forward error correction encoder which encode an input information signal into an error protected data bit stream. In addition, the communication unit includes a mode selector which enables either the error detection encoder or the forward error correction encoder used with a particular mode of operation of the communication unit. Further, a corresponding dual mode radio communication unit is provided having an error controller for generating estimated information signal samples according to a group of algorithms consisting of either an error detection algorithm or an error correction algorithm. In addition, the corresponding communication unit includes a mode selector for receiving a signal according to a particular one of the group of algorithms which is associated with a particular mode of operation of the corresponding communication unit.

Dual mode radio communication unit

A cellular communication system hops both signalling channels and traffics channels in a common hopping sequence. To obtain system information from the frequency hopping signalling channel, a subscriber unit waits on a predetermined frequency, or carrier, until the frequency hopped signalling channel arrives at the predetermined frequency. Once arrived, the subscriber unit obtains synchronization information, and information related to the hopping sequence, from the signalling channel during the hop. The subscriber unit may then hop in tandem with the system, obtaining further system information in subsequent hops. The cellular communication system supports mobile assisted handoff (MAHO) by allowing a subscriber unit to measure signalling channel of neighboring cells in a similar manner, and using the measurements to assist in communication handoff from a source cell to a neighboring cell.

Method and apparatus for frequency hopping a signalling channel in a

Apparatus is disclosed for enabling a mobile radiotelephone to automatically attempt to seize a radio channel in a multichannel radio communication system. The mobile radiotelephone scans the radio channels for a non-busy radio channel and provides an indication signal when detecting a non-busy radio channel. A counter which is continuously clocked by a clock signal is incremented for each clock cycle interval of the clock signal in response to the presence of the indication signal and is decremented for each clock cycle interval of the clock signal in response to the absence of the indication signal. Thus, the totalized count of the counter is proportional to the degree of radio channel blocking of the radiotelephone system. After an unsuccessful channel seizure attempt by the mobile radiotelephone user, time interval generating circuitry provides a random time interval that has a maximum magnitude that is inversely proportional to the totallized count of the counter. Thus, the maximum random time interval is shortest when the totallized count of the counter is greatest. At the end of the random time interval, circuitry automatically attempts to seize a radio channel and if unsuccessful, additional automatic channel seizure attempts are provided after corresponding random time intervals. Thus, overall radiotelephone system efficiency is enhanced by dynamically optimizing the average random time interval between automatic channel seizure attempts according to the degree of radio channel blocking.

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Arlington Heights, IL, United States of America

John R Haug