Title :
MQAM/CDMA for increased cellular capacity
Author :
Gejji, Raghvendra R.
Author_Institution :
Dept. of Electr. Eng., Western Michigan Univ., Kalamazoo, MI, USA
Abstract :
The CDMA (code division multiple access) technique can provide efficient multiple access to a large number of users. CDMA as a multiple access method can be combined with any desired modulation technique. The author considers the result of combining CDMA access with a high-efficiency modulation technique, e.g., 256-QAM (quadrature amplitude modulation), and whether the bandwidth efficiency of high-level QAM can be used to overcome the bandwidth inefficiency of CDMA. A mathematical model is built to compare cellular capacity obtained with and without MQAM-CDMA use. It is seen that MQAM-CDMA leads to reduced capacity, indicating that the advantages of the two schemes are not enough to overcome each other´s disadvantages
Keywords :
cellular radio; channel capacity; code division multiple access; quadrature amplitude modulation; 256-QAM; MQAM-CDMA; bandwidth efficiency; cellular capacity; code division multiple access; high-efficiency modulation; mathematical model; quadrature amplitude modulation; Amplitude modulation; Bandwidth; Error analysis; Forward error correction; Mathematical model; Multiaccess communication; Noise level; Quadrature amplitude modulation; Rayleigh channels; Signal to noise ratio;
Conference_Titel :
Vehicular Technology Conference, 1993., 43rd IEEE
Conference_Location :
Secaucus, NJ
Print_ISBN :
0-7803-1267-8
DOI :
10.1109/VETEC.1993.507007
