Abstract-We introduce a 16-dimensional constant-amplitude constellation that is generated by concatenating either four constant envelope quadrature-quadrature phase shift keying (CEQ 2 PSK) symbols from Saha and Birdsall or four CEQ 2 PSK symbols recently discovered by Cartwright and also introduced here. Our new constellation doubles the number of points available for data transmission without decreasing the distance between points or increasing energy, and may therefore be used in a trellis coded modulation (TCM) system without constellation expansion penalty. Because the new constellation has constant envelope, the modulation scheme becomes very attractive for nonlinear channels such as the magnetic recording channel or the satellite channel with traveling wave tube amplifiers.
Abstract-This paper presents a TCM scheme that uses a new expanded 16-Dimensional Constant Envelope Q 2 PSK constellation along with a simple convolutional encoder of rate 2/3. An effective gain of 2.67 dB over uncoded CEQ 2 PSK is achievable with low complexity, and without suffering from constellation expansion penalty. Larger coding gains are easily achieved with encoders of higher rates. In addition, an optimal hardware implementation of the required decoders is described.
Abstract-The authors present theoretical performance analysis and simulation results for Quadrature-Quadrature Phase Shift Keying (Q 2 PSK), Constant Envelope (CE) Q 2 PSK, and trelliscoded 16D CEQ 2 PSK in ideal bandlimited channels of various bandwidths. The performance of receivers with and without channel estimation is reported. Spectral analysis is presented for each system, in addition to MSK and expanded uncoded 16D CEQ 2 PSK. We show that the effects of bandlimiting are most severe for Q 2 PSK. Knowledge of the channel information aids 4D CEQ 2 PSK the least. Only 6.8 dB of SNR is needed for the TCM system for a bit error rate of 10 −5 for the narrowest channel bandwidth studied here, if the receiver has knowledge of the channel.
Abstract-This paper presents new visualization techniques for 4D Quadrature-Quadrature Phase Shift Keying (Q 2 PSK), Saha's Constant Envelope (CE) Q 2 PSK, and Cartwright's CEQ 2 PSK in ideal bandlimited channels. The signal diagrams analyzed are: time-signal eye patterns for 4D passband signals, 2D complex trajectory diagrams of baseband signals, and time-signal eye patterns for the 1D outputs of the baseband matched filter. These methods may be applied to other multidimensional modulation systems to obtain insight into the effects of noise, interference, and channel filtering.
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