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Combined coding and spreading in CDMA systems using maximum free distance convolutional codes

Pål Frenger (Institutionen för signaler och system, Kommunikationssystem) ; Pål Orten (Institutionen för signaler och system, Kommunikationssystem) ; Tony Ottosson (Institutionen för signaler och system, Kommunikationssystem)
Proceedings IEEE Vehicular Technology Conference, Ottawa, Canada Vol. 3 (1998), p. 2497-2501.
[Konferensbidrag, refereegranskat]

In CDMA systems maximum theoretical performance can be obtained by spreading with low-rate error control codes. Previously, orthogonal and superorthogonal codes have been proposed for this purpose. We present a family of rate-compatible low-rate convolutional codes with maximum free distance. The performance of these codes for spectrum spreading in a CDMA system is evaluated and shown to outperform that of orthogonal and superorthogonal codes as well as conventional coding/spreading schemes. We also show that our low-rate codes will give simple encoder and decoder implementation. With these codes any 1/n rate can be obtained regardless of the constraint length, resulting in a more flexible and powerful scheme than those proposed up to now.

Nyckelord: CDMA; low-rate convolutional codes; orthogonal codes; superorthogonal codes; rate-compatible; maximum free distance

Denna post skapades 2006-09-12. Senast ändrad 2013-06-13.
CPL Pubid: 15906


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Institutionen för signaler och system, Kommunikationssystem


Information Technology

Chalmers infrastruktur