non-orthogonal CDMA and IDMA
4.0
While orthogonal multiple access schemes such as Time Division Multiple Access (TDMA) or Frequency Division Multiple Access (FDMA) are implicitly too restrictive to achieve theoretical limits in fading channels, non-orthogonal CDMA or IDMA have the potential of achieving these limits [4]. Coding is typically used to improve the performance. At the receiver, iterative multiuser detection or interference cancellation followed by decoding is performed to approach maximum likelihood (ML) receiver performance without excessive complexity