Multiuser interference cancellation receivers for OFDMA uplink communications with carrier frequency offset.

The LDACS1 Physical Layer Design

“…Recalling that the shape of the window determines the spectrum of the OFDM subcarriers, the subcarrier spectra can be determined and the distortion induced by PB is identified as Inter-Carrier Interference (ICI). ICI can easily be reduced by subtracting the known impact of all other subcarriers from the considered subcarrier as applied for example for reducing ICI in OFDMA systems induced by frequency offsets (Fantacci et al, 2004).…”

BER Analysis of Uplink OFDMA in the Presence of Carrier Frequency and Timing Offsets on Rician Fading Channels

“…N ORTHOGONAL frequency-division multiple access (OFDMA) on the uplink, factors including 1) timing offsets (TOs) of different users that are caused by path delay differences between different users and imperfect timing synchronization and 2) carrier frequency offsets (CFOs) of different users that are induced by Doppler effects and/or poor oscillator alignments can destroy orthogonality among subcarriers at the receiver and cause multiuser interference (MUI) [1]- [8]. In practical wireless OFDMA systems, the detrimental effects of CFOs and TOs are reduced through tight closed-loop frequency/timing correction between the mobile transmitters and the base station (BS) receiver.…”

“…Such close-loop techniques are expensive in terms of feedback bandwidth and mobile transmit oscillator cost. Alternatively, the effects of MUI effects due to large CFOs and TOs can be countered through the use of interference cancellation techniques at the receiver [1]- [8].…”

“…However, we note that analytical characterization of the bit/symbol error performance of uplink OFDMA in the presence of CFOs and TOs has not been adequately addressed in the literature. Most bit error rate (BER) evaluations in uplink OFDMA are based on simulations, e.g., [1]- [8].…”

A multiuser interference cancellation scheme for uplink OFDMA

“…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.…”