Title :
Mobile channel estimation for decision directed RAKE receivers operating in fast fading radio channels
Author :
Auer, Gunther ; Povey, Gordon J R ; Laurenson, David I.
Author_Institution :
Dept. of Electr. Eng., Edinburgh Univ., UK
Abstract :
The authors describe a robust channel prediction technique for a direct sequence spread spectrum (DS-SS) system in a fast fading environment. For improved performance the RAKE filter taps are coherently combined, hence accurate channel estimation is required. An FIR type linear prediction filter for each RAKE filter tap is used to estimate the channel response. In order to do this, the data decisions are fed back to the prediction filter. The stability of the proposed system is achieved through differential encoding of the data bits. It is demonstrated through simulations that the performance of the proposed decision directed receiver is better than that of an idealised receiver where channel estimation is not corrupted by decision feedback errors (e.g. by means of employing a pilot signal). The channel estimate can be significantly improved by employing a second stage channel estimation filter
Keywords :
FIR filters; Rayleigh channels; diversity reception; encoding; filtering theory; land mobile radio; parameter estimation; phase shift keying; prediction theory; radio receivers; spread spectrum communication; BPSK; DS-SS system; FIR type linear prediction filter; RAKE filter taps; Rayleigh fading channel; channel response; data bits; data decisions; decision directed RAKE receivers; decision feedback errors; differential encoding; direct sequence spread spectrum; diversity; fast fading radio channels; mobile channel estimation; performance; pilot signal; second stage channel estimation filter; simulations; system stability; AWGN; Bandwidth; Channel estimation; Fading; Finite impulse response filter; Multipath channels; Nonlinear filters; Phase estimation; RAKE receivers; Stability;
Conference_Titel :
Spread Spectrum Techniques and Applications, 1998. Proceedings., 1998 IEEE 5th International Symposium on
Conference_Location :
Sun City
Print_ISBN :
0-7803-4281-X
DOI :
10.1109/ISSSTA.1998.723850