This paper presents the results of work at TRW in developing a multi-carrier receiver for cellular base station applications. Replacing existing single carrier receivers with a multi-carrier receiver has the potential to significantly increase the capacity of existing mobile phone networks and reduce the cost per carrier. Implementation of a multi-carrier receiver has been limited by the large dynamic range requirements for GSM/EDGE and WCDMA standards, with the GSM 900 MHz band presenting the greatest challenge. TRW is leveraging several proprietary technologies that enable and facilitate this development, including the latest product in a series of high performance analog-to-digital converters (ADCs). The stressing requirements for very high dynamic range (up to 108 dB SNR), wide bandwidth, and high linearity are met by employing a delta-sigma ADC that redefines the state-of-the-art. TRW's world-class InP process is used to fabricate devices capable of the high level of oversampling needed to satisfy the demanding performance values. We describe the receiver architecture and present preliminary test results from our first engineering model, demonstrating the practicality of a multi-carrier receiver for cellular base stations.

The universal source coding theorem for stationary sources states that, by using a preselected code with sufficiently large block length, any stationary source can be encoded arbitrarily close to the optimum performance theoretically attainable for the source. The code construction typically used to prove this theorem offers no performance guarantees for nonstationary sources. A code construction (based on composition classes) is described which is shown to be universal for stationary sources. In addition, this code construction guarantees that the distortion for any block in the sequence will not exceed a maximum value determined by its composition.

An example of the growing influence of the microprocessor in communications is illustrated in this description of the payload bit synchronizer and other related payload signal processing functions for the Space Shuttle. Stored in firmware the microprogrammed control at 2.56 M-instructions/s accomplishes bit synchronization, matched filter detection, NRZ-Lconversion and frame synchronization for some thirty combinations of PCM formats and data rates.