Title :
High efficient transmission on digital microwave radio
Author :
Ryu, T. ; Maeda, S. ; Ozaki, S. ; Hashimoto, H. ; Moreland, A.J.
Author_Institution :
NEC Corp., Tokyo, Japan
Abstract :
The high-capacity digital microwave radio (DMR) currently used for trunk lines has a 4.5-b/Hz efficiency using 64 QAM (quadrature amplitude modulation) modulation and transmits 135-Mbps data within a 30-MHz bandwidth. When dual-polarization transmission techniques are used, an efficiency of 9 b/Hz can be achieved and transmission of 270 Mb/s data in the 30-MHz bandwidth becomes possible. The features and configuration of a 64 QAM DMR transmission system using dual polarization are presented. It is concluded that, currently, the 64 QAM DMR with XPIC (cross-polarization interference cancellers) is the most feasible system from both the technical and economical viewpoints when a capacity of higher than 135 Mb/s is required
Keywords :
amplitude modulation; digital radio systems; electromagnetic wave polarisation; microwave links; 135 Mbit/s; 270 Mbit/s; 30 MHz; 64 QAM; cross-polarization interference cancellers; digital microwave radio; dual-polarization transmission; high efficiency transmission; high-capacity; quadrature amplitude modulation; trunk lines; Bandwidth; Bit rate; Degradation; Demodulation; Fading; National electric code; Polarization; Quadrature amplitude modulation; Satellite communication; System performance;
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.1989.64000
