RF coding in MMIC six port receiver

In this paper, RF coding is used with a six port direct digital QPSK receiver in an AWGN channel. The proposed direct conversion wideband six-port millimeter wave receiver meets the needs of MMIC mass-market wireless communications. RF coding is used for the first time in this type of receiver. Direct conversion receivers offer a unique advantage for wireless communications by reducing circuit complexity and allowing a higher level of circuit integration than the traditional heterodyne receivers. Six-port direct conversion receivers have been proposed as both hardware and multimode or software receivers operated with DSP programmed for a number of modulation schemes. This paper presents RF-coding results obtained on a new six-port based hardware type receiver designed for QPSK millimeter wave communications. In the transmitter end, QPSK modulation and LPM (linear phase modulation) modulator are used to generate the RF coding signal, and in the receiving end, a MMIC six-port receiver is used. In order to obtain the information bits, at the end of the output of six port receiver, a decision circuit is used, from the judgement circuit the input signal can be determined from the waveform of the output. For different LPM signals, different waveforms of the six-port output are presented and the results will be discussed. This method has a great advantage of simplicity and easy to use.