A New Grouping-ML Detector with Low Complexity for SC-FDMA Systems

Abstract

In this paper, we propose a new grouping-maximum likelihood detector (GMLD) for single carrier-frequency division multiple access (SC-FDMA) systems. The proposed detector performs local maximum likelihood (ML) detection by grouping the received symbol block based on orthogonal projection to reduce the complexity of ML detector. As a result, the proposed detector offers lower complexity than the ML detector, while its performance approaches that of the ML detector. In addition, the efficient group size to guarantee the lowest complexity and the BER performance close to the ML is also presented.

A ML-Based Detector Considering Transmit Power Allocation for SC-FDMA Systems

“…After that, the detected symbol,ŝ Q 2 −i+1 , is extracted from (6), s Q 2 +i is detected using ML detection [7]. When s Q 2 −i+1 and s Q 2 +i are detected using ML detection at ith iteration, M candidates are selected in ascending order of their ED out of the total C candidate symbols (M ≤ C), which is called M -algorithm [10].…”

“…When s Q 2 −i+1 and s Q 2 +i are detected using ML detection at ith iteration, M candidates are selected in ascending order of their ED out of the total C candidate symbols (M ≤ C), which is called M -algorithm [10]. It can enhance the BER performance [7].…”

“…After the received signal in the SC-FDMA receiver undergoes a CP removal, N -point DFT and Q-point IDFT, it can be converted as follows [6] [7]:…”

“…After s (k) passes Q-point DFT, N -point IDFT and CP insertion, the signal of the kth user is transmitted [7]. The CP length is assumed to be longer than the maximum delay spread of the channel, so that no inter-block interference occurs.…”

“…We proposed a new grouping-ML detector (GMLD) to guarantee high performance and reasonable complexity in [7]. In this paper, we propose a new detection algorithm called the duo ML detector with transmit power allocation (DMLD-TPA) to enhance BER performance more and keep complexity low, especially when the transmit block size is big.…”