Symbol Detection in CDMA-OFDM Coexistence

Abstract:
Code division multiple access (CDMA) and Orthogonal frequency division multiplexing (OFDM) are two techniques that are being commonly used in most wireless communication systems. In this paper we examine the coexistence of the above schemes through a two user communication system, i.e., one user transmits using CDMA and the other transmits using OFDM. Using an OFDM based receiver, we derive the received symbols at the output of each branch of the OFDM demodulator. The symbols transmitted by the CDMA user are then detected using the minimum power distortionless response (MPDR) approach, an array processing technique commonly used in beamforming. Through simulations, we then show that the MPDR method is indeed very efficient in suppressing the OFDM interference.