Title :
A power efficient embedded modulation scheme for addressing multiple users in the downlink
Author :
Janssen, Gerard J M
Author_Institution :
Wireless & Mobile Commun. Group, Delft Univ. of Technol., Netherlands
fDate :
30 May-1 June 2005
Abstract :
A power efficient embedded QAM (EQAM) modulation scheme, for addressing multiple users simultaneously in the downlink of a cellular system, is proposed. The EQAM modulation is based on stacking a number of M-PSK (M = 2,4) signals each intended for a different user. The optimum phase relations between the users´ signals and the required link quality dependent amplitudes, are given. The power penalty is evaluated for geometrically related link qualities and for a number of heuristic user assignment schemes in a single cell system. Compared to a conventional QAM-scheme with the same spectral efficiency, the power penalty for EQAM can be substantially lower, provided that users with sufficiently different link qualities are addressed with the same signal.
Keywords :
cellular radio; quadrature amplitude modulation; radio links; QAM; cellular system; downlink; heuristic user assignment schemes; link quality; multiple users; power efficient embedded modulation scheme; power penalty; Base stations; Digital video broadcasting; Downlink; Interference; Mobile communication; Narrowband; Phase shift keying; Power system modeling; Quadrature amplitude modulation; Stacking;
Conference_Titel :
Vehicular Technology Conference, 2005. VTC 2005-Spring. 2005 IEEE 61st
Print_ISBN :
0-7803-8887-9
DOI :
10.1109/VETECS.2005.1543659
