Title :
A decision-directed constant modulus algorithm for higher-order source constellations
Author :
Endres, T.J. ; Hulyalkar, S.N. ; Strolle, C.H. ; Schaffer, T.A. ; Casas, R.A.
Author_Institution :
NxtWave Commun., Langhorne, PA, USA
Abstract :
This paper discusses methods for calculating and implementing the update error term for the popular blind equalization algorithm known as Godard´s (1980) algorithm, or the constant modulus algorithm (CMA), without the use of multipliers so that the chip area and signal latency are both substantially reduced. A decision-directed CMA update term is derived for higher-order (non-constant modulus) source alphabets. The modified update error term can be calculated using a look-up table in place of costly multipliers and adders. Baseband and passband implementations for one-dimensional and two-dimensional signaling are discussed
Keywords :
adaptive equalisers; blind equalisers; decision theory; higher order statistics; table lookup; telecommunication signalling; Godard´s algorithm; adaptive equalizers; baseband implementation; blind equalization algorithm; chip area; decision-directed CMA update term; decision-directed constant modulus algorithm; higher-order source constellations; higher-order statistics; look-up table; modified update error term; nonconstant modulus source alphabets; one-dimensional signaling; passband implementation; signal latency; two-dimensional signaling; Baseband; Costs; Delay; Equalizers; Error correction; Passband; Quadrature amplitude modulation; Quantization; Robustness; Table lookup;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 2000. ICASSP '00. Proceedings. 2000 IEEE International Conference on
Conference_Location :
Istanbul
Print_ISBN :
0-7803-6293-4
DOI :
10.1109/ICASSP.2000.860126
