Title :
Orthogonality invariant of spreading codes in MC-CDMA system under carrier frequency offset
Author :
Jao, Chin-Kuo ; Wei, Shyue-Win
Author_Institution :
Grad. Inst. of Commun. Eng., Nat. Chi Nan Univ., Puli
Abstract :
Carrier frequency offset (CFO) may cause multiple access interference (MAI) among users in multi-carrier code division multiple access (MC-CDMA) system. In the paper the code sensitivity of spreading codes and its correlative to the CFO is observed. An important property of orthogonality invariant for Walsh Hadamard spreading codes under CFO is presented. By partitioning spreading codes into several mutually orthogonal groups, if the spreading codes are chosen from different groups, free MAI can be maintained for any values of CFO. The characteristic can help us to develop code selection algorithm for choosing appropriate spreading codes that has less MAI under frequency offset transmission.
Keywords :
Hadamard codes; code division multiple access; MC-CDMA system; Walsh Hadamard spreading codes; carrier frequency offset; frequency offset transmission; multi-carrier code division multiple access; multiple access interference; spreading codes; Error correction; Error correction codes; Fading; Frequency conversion; Modulation coding; Multicarrier code division multiple access; Multiple access interference; Multiuser detection; OFDM; Quadrature phase shift keying; CFO; MAI; MC-CDMA; spreading code;
Conference_Titel :
Personal, Indoor and Mobile Radio Communications, 2008. PIMRC 2008. IEEE 19th International Symposium on
Conference_Location :
Cannes
Print_ISBN :
978-1-4244-2643-0
Electronic_ISBN :
978-1-4244-2644-7
DOI :
10.1109/PIMRC.2008.4699504
