Title :
Advanced techniques for super multi-carrier digital microwave radio with trellis-coded 256 QAM modulation
Author :
Nakamura, Yasuhisa ; Ohtsuka, Hiroyuki ; Aikawa, Satoru ; Takanashi, Hotoshi
Author_Institution :
NTT Radio Commun. Syst. Lab., Japan
Abstract :
The latest techniques for realization of an outage-free digital microwave radio (DMR) are presented. Three major techniques, trellis-coded 256 QAM (quadrature amplitude modulation) modulation, super multicarrier transmission, and microwave signal processing (MSP), are described. The BER (bit error rate) and signature characteristics of the trellis-coded 256 QAM system are simulated, and its validity as a fading countermeasure is indicated. The Viterbi-decoder LSI and effect of phase error on the TCM modem are also presented. An experiment using a 4, 8, 40-carrier 256 QAM modem showed an overall outage improvement factor of nearly 500 times due to a 40-carrier system. Lastly, the microwave signal processing technique, including IF stage (carrier) signals for DMR systems, is presented. An all-digital 256 QAM modulator was constructed and showed superior performance with no adjustment
Keywords :
amplitude modulation; carrier communication; digital radio systems; error statistics; intersymbol interference; microwave links; 256 QAM modulation; BER; IF stage signals; ISI environment; TCM modem; Viterbi-decoder LSI; all-digital modulator; bit error rate; digital microwave radio; fading countermeasure; microwave signal processing; outage-free; phase error; signature characteristics; super multi-carrier; super multicarrier transmission; trellis-coded; Bit error rate; Digital modulation; Digital signal processing; Fading; Frequency; Microwave theory and techniques; Modems; Quadrature amplitude modulation; Signal processing; Sliding mode control;
Conference_Titel :
Global Telecommunications Conference and Exhibition 'Communications Technology for the 1990s and Beyond' (GLOBECOM), 1989. IEEE
Conference_Location :
Dallas, TX
DOI :
10.1109/GLOCOM.1989.64001
