| We demonstrate how the performance of offset quadrature phase-shift keying (OQPSK) and its variants of Feher-patented QPSK (FQPSK) and Shaped Offset QPSK (SOQPSK) (collectively known as the ARTM Tier-1 waveforms) in single input single output (SISO) system could change with the channel fading parameters. The bit error rate expression of offset QSPK and ATRM Tier-1 waveforms over the aeronautical telemetry multipath channel has been derived. Simulations show that for the case of a single multipath ray, the BER gets worse with increasing Gamma for a fixed delay, and that the BER has a quasi-periodic property for fixed Gamma and increasing tau. For the case of two multipath rays, the multipath component characterized by large amplitude and small delay is the main factor of the BER degradation, while the BER is not very sensitive to the change of multipath delay. Analysis of the average bit error probability shows that a relatively high error floor at approximately 10-2 occurs for |Gamma1| ≥ 0.5.;It is demonstrated that a concatenated system based on an orthogonal space-time block code and a trellis code, optimized for single-input, single-output fading channel, outperforms a space-time trellis code for a 2 x 1 system. The space-time block code orthogonalizes the channel seen by the outer code and this simplifies the computations required for decoding. The advantages of orthogonalization are achieved at the expense of rate. In the examples presented, the codes were chosen to have roughly equivalent bit error rate performance and identical code rates: the complexity was compared.;When offset quadrature phase-shift keying (OQPSK) is used in multiple input multiple output (MIMO) environment, orthogonal space-time block codes can be applied to waveforms to orthogonalize a space-time coded multiple-input, multiple-output link. For offset QPSK, this technique has the advantage of eliminating the I/Q interference associated with simultaneous transmission of offset QPSK waveforms. In addition, orthogonalization presents uncorrelated noise samples to the space-time trellis decoder. As a consequence, a less complex space-time decoder (relative to what would be required without orthogonalization) can be used. |
