Motorola Corporation

Ken Jakobsen

Kenneth J Crisler

Rod N Averbuch

Guy George Romano

John Hughes

Data for transmission may be convolutionally encoded and punctured prior to transmission. The invention relates to a method and apparatus for decoding such data. In accordance with the invention, a table of error metrics is prepared when a given group (Gt) of n bits is received at a particular time (t). The error metrics (Mti) are calculated for comparisons of the n bits received with each possible permutation (Pi) of n bits. These error metrics (Mti) are placed in the metric table. Next a look-up table (Tt) is consulted which lists each state change (Sj) which the encoder could have undergone at the particular time (t) together with the permutation (Pi) of bits which would have been produced by the encoder for that state change. The look-up table (Tt) is particular to the puncturing scheme which the encoder uses at the particular time (t). The metric table is then used to add to the look-up table (Tt) the error metric (Mti) appropriate to each state change (Si) in the table (Tt). These error metrics are then used to update the cumulative metric of the decoder.

Method and apparatus for Viterbi decoding of punctured codes

A cellular radio communications system comprises: at least one base station for broadcasting radio signals to mobile stations within a cell; a mobile station addressable using IP addresses; and a first controller in the cell of the cellular radio communications system, the first controller being adapted: (i) to receive a request from the mobile station that the cellular radio communication system assign to the mobile station the static IP address previously assigned to the mobile station outside of the cell; (ii) in response to the request from the mobile station, to check with a second controller associated with the location where the mobile station was previously registered that the static IP address has not been assigned to another mobile station; and (iii) to assign the static IP address previously assigned to the mobile station, outside of the cell, to the mobile station for use in the cell, if the static IP address has not been assigned to another mobile station. Alternatively, the first controller may perform the check for availability of the static IP address with a controller associated with the location where the static IP address is registered. The invention also comprises methods of mobile station registration in cellular radio communication systems. The invention enables roaming by a mobile station between cellular systems which are under the control of different Software and Measurement Infrastructures. Mobile stations may be adapted to check one or more timers prior to making the static IP address request.

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Vaerlose, Denmark

Ken Jakobsen