A combined OFDM/SDMA approach

Stochastic Optimization Assisted Joint Channel Estimation and Multi-User Detection for OFDM/SDMA

“…The ML-MUD As a benefit of the CP, the OFDM/SDMA symbols do not overlap and hence SDMA MUD processing can be applied on a per-carrier basis [1,2]. Hence, the task of the MUD is to recover the transmitted signals X[s, k] ∈ C U ×1 of the U users from the received signals formulated in Equation (1) …”

“…As one of the most wide-spread multiple antenna aided systems, Orthogonal Frequency-Division Multiplexing/Spatial Division Multiple Access (OFDM/SDMA) [2] exploits the advantages of both OFDM and SDMA, which increase the attainable spectral efficiency by sharing the same bandwidth and time slots by several users roaming in different geographical locations, which are differentiated by their unique, user-specific 'spatial signature', i.e. by their Channel Impulse Responses (CIRs).…”

Multiple antenna aided OFDM employing minimum bit error rate multiuser detection

“…A variety of linear multiuser detectors have been proposed for performing the separation of OFDM users based on their unique, user-specific spatial signature, provided that their channel impulse response was accurately estimated [1,2]. The most popular design strategy is constituted by the minimum mean squared error (MMSE) multiuser detector (MUD).…”

“…In an effort to increase the achievable system capacity of an OFDM system, antenna arrays can be employed for supporting multiple users in a space division multiple access (SDMA) communications scenario [1,2]. A variety of linear multiuser detectors have been proposed for performing the separation of OFDM users based on their unique, user-specific spatial signature, provided that their channel impulse response was accurately estimated [1,2].…”

MMSE Soft-Interference-Cancellation Aided Iterative Center-Shifting K-Best Sphere Detection for MIMO Channels

“…SYSTEM MODEL In this paper a spatial-division-multiplexing (SDM) orthogonal-frequency-division-multiplexing (OFDM) system equipped with M transmit antennas and N receiver antennas is considered [3]. The subcarrier-related MIMO-OFDM system model considered is given by [3,4]:…”