Unequal error protection (UEP) codes find applications in broadcast cbannels, as well as in otber digital communication systems, where messages bave ditTerent degrees of importance, In this correspon­ dence, binary linear UEP (LUEP) codes combined with a Gray mapped QPSK signal set are used to obtain new efficient QPSK block-modulation codes for unequal error protection. Several examples of QPS...

This paper presents a new practical QPSK receiver that uses digitized samples of incoming QPSK analog signal to determine the phase of the QPSK symbol. The proposed technique is more robust to phase noise and consumes up to 89.6% less power for signal detection in demodulation operation. On the contrary, the conventional QPSK demodulation process where it uses coherent detection technique requi...

OFDM is a powerful multicarrier transmission technique used extensively for wireless applications. High PAPR is one of the deleterious problems of OFDM. This paper reviews basic OFDM system and PAPR problem associated with it. Also, the construction of M-QAM particularly 16-QAM sequences using QPSK Golay sequences over 4  is conferred. It is elucidated that a 16-QAM constellation can be writte...

The authors present theoretical performance analysis and simulation results for Quadrature-Quadrature Phase Shift Keying (QPSK), Constant Envelope (CE) QPSK, and trelliscoded 16D CEQPSK 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 ...

In this article we present an efficient approach for the implementation of optimum maximum likelihood decoding of QPSK modulated multiple-input-multiple-output data streams. The proposed method does not compromise optimality of the detection algorithm. Instead it uses the special properties of QPSK modulation together with algebraic transformations and architectural optimizations to achieve ver...