Abstract: A system and a method for supporting a multi-user text chat service in a mobile network uses existing standards and products while providing efficient use of radio frequency and signaling resources. The system includes a computing element for converting messages between two known formats and which further provides security, billing and other administrative functions. The system is thus able to combine a point-to-point messaging protocol for originating a message and a broadcast protocol for receiving the message.

Abstract: An apparatus and method for intelligent message insertion during a targeted telephone or Internet chat room call, that provides a way to identify pre-defined content in conversations of targeted subscribers, and to insert commercial messages, for example, that are targeted either on the basis of subject relevance and/or a previously acquired subscriber profile. The apparatus may employ an automatic speech recognition (ASR) engine and/or an automatic text recognition engine for recognizing a pre-defined word, or sequence of words, and for selecting and inserting relevant and timely messages during a live conversation, according to the content of this conversation. The recognition engine detects words (for example, “holidays”, “flowers”, “pizza”, etc.), as spoken or written by the subscriber and the called party.

Abstract: The invention provides a block-encoded modulation scheme using multi-level partitioning techniques. This scheme is made transparent to phase ambiguities of ±&pgr;/2 and of &pgr;, by means of differential encoding and appropriate mapping, it is applicable to 16-QAM modulation, and it has theoretical encoding gain that is optimal for the rate of the code. The decoder associated with this scheme uses the Wagner algorithm which is much less complicated to implement than the Viterbi algorithm or than the Reed-Solomon algorithm.

Abstract: The invention relates in particular to a method of compensating differences in group propagation times between first and second analog filters of a transmitter of signals in phase quadrature, and between third and fourth analog filters of a receiver of signals in phase quadrature. The method consists in: applying the output signals from the first and second filters respectively to the third and fourth analog filters so as to measure a time difference .DELTA.1 equal to: ?Tx+Rx!-?Ty+Ry! where Tx, Rx, Ty, and Ry are respective propagation times for the signals through the first, second, third, and fourth filters; applying the output signals from the first and second filters respectively to the fourth and third analog filters so as to measure a time difference .DELTA.2 equal to: ?Ty+Rx!-?Tx+Ry! and determining weighting coefficients from the differences .DELTA.1 and .DELTA.