Ericsson Gmbh

Larry William Massingill

Torbjorn Wilson Solve

Amer A Hassan

Yi-Pin Eric Wang

Stan L Reinhold

Kumar Balachandran

Carsten Hoirup

Javor Kolev

Stanley L Reinhold

Eric Yi-Pin Wang

Richard Edward Weiss

Methods and systems for acquiring service for a user terminal with a satellite communications system are provided wherein geographic information is received via an electromagnetic transmission at the user terminal defining a location of the user terminal. A control channel is selected corresponding to one of the spot beams covering the location of the user terminal using the geographic information. The user terminal acquires service from the satellite communications system over the control channel. The geographic information enables the user terminal to shorten the search time by searching those channels which correspond to the geographic region determined from the geographic information.

Methods and systems for acquiring service within a satellite

A method and apparatus for reducing power consumption in a mobile terminal having a receiver for receiving a time multiplexed message distributed over a plurality of time slots by receiving a first subset of the plurality of time slots so as to receive a first portion of the time multiplexed message corresponding to the first subset of the plurality of time slots. The mobile terminal then determines from the first portion of the time multiplexed message if additional time slots of the time multiplexed message need to be received by the mobile terminal. The mobile terminal receives a second subset of the plurality of time slots so as to receive a second portion of the time multiplexed message if the mobile terminal determines from the first portion that additional portions of the time multiplexed message are to be received by the mobile terminal. This first portion of the message is preferably independently decodeable from the remainder of the message.

Methods and systems for reduced power operation of cellular mobile

A method and associated apparatus for deriving a random reference value from a paging signal transmitted between a network station and a user terminal of a radiotelephonic communication system, such as a satellite-cellular communication system. When communication is to be initiated, a paging signal is transmitted by a network station to a user terminal. When the user terminal detects the paging signal, a random reference value is derived from a portion of the paging signal, and response signal, responsive to the random reference value is generated and transmitted to the network station. When the network station receives the response signal, it compares it to an expected response value to authenticate the user terminal.

Apparatus and method for deriving a random reference number from paging

A method for increasing the control channel capacity of a control station in a communications system. According to the method, in an idle mode of operation, a mobile station receives and processes data during more than one time slot per frame. As a result, additional channel structures are made possible such that additional data can be broadcast to a mobile station without restructuring a conventional slot format.

Method for increasing control channel capacity in a communication system

A method for distinguishing between in-band signaling and user data transmissions of a communication system. The method includes the assignment of separate training bit sequences, one for in-band signaling transmissions and another for user data transmissions. During transmission, the training bit sequence associated with the type of transmission being sent is used as the training bit sequence. The method further includes the correlation of the received training bit sequence with both the training bit sequence assigned to in-band signaling and the training bit sequence assigned to user data. The training bit sequence having the highest correlation energy indicates the type of data contained in the communication transmission.

Method and apparatus for distinguishing in-band signaling from user data

A power saving method for maintaining synchronization in a power-limited communication system, such as a satellite-based TDMA mobile radiocommunication system. According to exemplary embodiments, the satellite transmits abbreviated bursts containing only synchronization information during intervals when no other control information is required by the receiving mobile unit, reducing power consumption during these intervals.

Power-saving method for providing synchronization in a communications

In a time division multiple access (TDMA) radiotelephone communications system, a spread spectrum random access channel signal representing a random access message is communicated from a radiotelephone to a central station according to a spreading sequence. In response, a TDMA radiotelephone communications channel is assigned to the radiotelephone. A time division multiplexed radiotelephone communications signal is communicated between the radiotelephone and the central station on the assigned TDMA radiotelephone communications channel over a time division multiplexed carrier frequency band. Preferably, in communicating the spread spectrum random access channel signal, a random access channel signal, representing the random access channel message, is direct sequence modulated according to the spreading sequence to produce a direct sequence modulated random access channel signal. According to a two-stage detection aspect, a synchronization sequence may be associated with a plurality of spreading sequences. The synchronization sequence may be first detected from the communicated spread spectrum random access channel signal, and in response to detection of the synchronization sequence, one of the plurality of spreading sequences associated with the detected synchronization sequence may be detected. A station identification may be assigned to the radiotelephone, with the station identification preferably represented by a digital station identification word. The synchronization sequence and the spreading sequence may be identified from the station identification word, thus associating the synchronization and spreading sequences. The spreading sequence may also be randomly generated from the station identification word.

Spread spectrum random access systems and methods for time division

A method for transmitting random access signals from a mobile unit to a satellite or other control station which requires the transmission of less information than in conventional terrestrial cellular or proposed mobile satellite systems. According to the method, the mobile unit acquires synchronization from the satellite and transmits reduced random access information to the satellite, and the satellite calculates time adjustment information for the mobile units based on the reduced random access information. The random access information is reduced by predetermining a slot number for each mobile unit, and by transmitting only the odd or even status of the frame number desired by the mobile unit.

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Selma, NC, United States of America

Larry William Massingill