MMSE Receiver for Multiuser Interference Cancellation in Uplink OFDMA

Abstract

Abstract-In uplink orthogonal frequency division multiple access (OFDMA) systems, multiuser interference (MUI) occurs due to different carrier frequency offsets (CFO) of different users at the receiver. In this paper, we present a minimum mean square error (MMSE) based approach to MUI cancellation in uplink OFDMA. We derive a recursion to approach the MMSE solution. We present a structure-wise and performance-wise comparison of this recursive MMSE solution with a linear PIC receiver as well as other detectors recently proposed in the literature. We show that the proposed recursive MMSE solution encompasses several known detectors in the literature as special cases.

CFO Compensation for Uplink OFDMA Systems with Conjugated Gradient

“…To mitigate the complexity, the scheme in [5] was introduced, but the performance is severely degraded due to the large MAI. In [6], the authors proposed interference cancellation schemes to iteratively cancel the remaining MAI. Also, the scheme in [3] was developed to further improve the performance by recalculating the coefficients of the MMSE equalizer for each MU at each stage.…”

A multiuser interference cancellation scheme for uplink OFDMA

“…Recent research has been witnessing increased focus on orthogonal frequency multiple access (OFDMA) on the uplink [1]- [10]. The performance of OFDM/OFDMA systems depend to a large extent on how well the orthogonality among different subcarriers are maintained at the receiver [11], [12].…”

“…This needs additional signaling and hence reduces system throughput. An alternate approach is to apply interference cancellation (IC) techniques at the base station receiver [8]- [10]. Recently, in [9], Huang and Letaief presented an IC approach which performs CFO compensation and MUI cancellation in frequency domain using circular convolution.…”

“…Structure-wise, a common feature in CLJL [6], HLCC [9], and MMSE [10] schemes is that all these detectors/cancellers first perform a single DFT operation on the received samples and the resulting DFT output vector is further processed to achieve CFO compensation and MUI cancellation using circular convolution. A new contribution in this paper is that we propose and analyze an alternate MUI cancellation receiver structure which first performs CFO compensation in time domain, followed by K DFT operations (where K is the number of users) and multistage linear parallel interference cancellation (LPIC) on these DFT outputs.…”

Cancellation of Multiuser Interference due to Carrier Frequency Offsets in Uplink OFDMA

“…ECENT research has been witnessing increased focus on orthogonal frequency multiple access (OFDMA) on the uplink [1]- [10]. The performance of OFDM/OFDMA systems depend to a large extent on how well the orthogonality among different subcarriers are maintained at the receiver [11], [12].…”