An Assessment Of The Bit-Error-Rate Performance Of QPSK, 8PSK, 8PSK/TCM and GMSK via the Tracking And Data Relay Satellite System 650 Mhz-Wide Ka-Band Channel

Abstract

In June 2000, NASA launched the first of three next generation Tracking and Data Relay Satellites (TDRS-H, I and J) that incorporate a 650 MHz-wide Ka-band Single Access Return (KaSAR) service using the 25.25 – 27.5 GHz space-to-space link (SSL) allocation. In parallel with this space segment upgrade, NASA has been upgrading the ground segment to support the 650 MHz-wide Ka-band service. As part of this upgrade effort, analyses were performed to determine the fidelity requirements of the ground terminal equipment and to estimate the implementation loss of the Tracking and Data Relay Satellite System (TDRSS) KaSAR 650 MHz service for customer data rates from 600 Mb/sec to 1.2 Gb/sec using various modulation schemes. This paper summarizes the results of the TDRSS KaSAR 650 MHz service implementation loss analysis. 1.0 Introduction Modifications to the TDRSS ground segment to support a KaSAR 650 MHz service are being performed under the NASA Goddard Space Flight Center (GSFC) Ka-Band Transition Product (KaTP). In support of these modifications, simulation and analytical models were developed to determine appropriate fidelity requirements for the new hardware, evaluate vendor bids and hardware noncompliances, and estimate the total implementation loss of the TDRSS KaSAR 650 MHz service. The simulation models were developed to incorporate the primary customer transmitter and TDRSS distortions including modulator gain and phase imbalance, phase noise, channel gain and group delay variation, amplifier nonlinearities, and spurs. The output of the models was Bit-Error-Rate (BER) performance versus Eb/No. Using the models as well as hardware requirements and measurement data, a comprehensive assessment of the TDRSS KaSAR 650 MHz service implementation loss was performed. This assessment evaluated the performance of the service for a variety of modulation schemes including Offset Quadrature Phase Shift Keying (OQPSK), 8-ary Phase Shift Keying (8PSK), Trellis Coded 8-ary Phase Shift Keying (8PSK/TCM) and Gaussian Minimum Shift Keying (GMSK). The analysis focused on customer data rates between 800 Mb/sec and 1 Gb/sec, however, a range of 600 Mb/sec to 1.2 Gb/sec was analyzed.