Low-complexity Successive Interference Cancellation Research Articles

Low complexity successive interference cancellation receiver for DCT-NOMA-OFDM system with CFO

The integration of orthogonal frequency division multiplexing (OFDM) with non-orthogonal multiple access (NOMA) for multiplexing of multiple users has been previously studied for the 5G and beyond networks. It has been used to fulfill the demand for high spectral and energy efficiency, massive connectivity, and ultra-low latency with user fairness. However, with higher mobility, the residual interference power remaining after the Successive interference cancellation (SIC) and equalization process significantly deteriorates the system’s symbol error rate (SER) performance. This paper considers a downlink discrete cosine transform (DCT) based NOMA-OFDM system with equalization and interference-compensation jointly in the fractional Fourier domain (FFD). The traditional full matrix compensation strategy attracts a lot of complexity. So, the proposed system architecture considers a low complexity banded joint equalization and interference-compensation (JEIC) method for each user equipment (UE). With the help of the proposed architecture, an SNR gain of 3 dB in the case of UE-2 and 8 dB in the case of UE-1 has been achieved over the conventional system in the presence of normalized carrier frequency offset (ϵ) = 0.05 at BER =10−3. Further, in the presence of ϵ= 0.1, the UE-2 with the proposed architecture gains 5 dB over the conventional system at 1×10−3 SNR range. The proposed architecture brings the performance of the system similar to the interference-free system with reduced complexity in O(N) compared to the full matrix compensation scheme having O(N3) complexity.

Low-Cost Design of Massive Access for Cellular Internet of Things

In this paper, we investigate the issue of low-cost design of massive access for cellular internet of things (IoT) over spatially correlated Rician fading channels. Specifically, by exploiting a low-overhead transmission protocol, a base station (BS) equipped with a large-scale antenna array and low-resolution analog-to-digital converters (ADCs) is deployed to serve a massive number of IoT devices with low-complexity successive interference cancellation (SIC) receivers. We first analyze the impacts of the low-cost design on the system performance and derive closed-form expressions for uplink and downlink spectral efficiencies of the cellular IoT. Then, for alleviating the negative impacts of the low-cost design, we propose an algorithm allocating the time for channel estimation, uplink data transmission, and downlink data transmission in a data frame. Finally, extensive simulation results confirm the effectiveness of the proposed low-cost design for the cellular IoT.

VLSI Implementation of a Fully-Pipelined K-Best MIMO Detector with Successive Interference Cancellation

Multiple-input multiple-output (MIMO) technology is envisaged to play an important role in future wireless communications. To this end, novel algorithms and architectures are required to implement high-throughput MIMO communications at low power consumption. In this paper, we present the hardware implementation of a modified K-best algorithm combining conventional K-best detection and low-complexity successive interference cancellation at different levels of the tree search. The detector is implemented using a fully-pipelined architecture, which detects one symbol vector per clock cycle. To reduce the power consumption of the entire receiver unit, costly symbol-rate operations such as multiplication are eliminated both within and outside the detector without any impact on the performance. The hardware implementation of the modified K-best algorithm achieves area and power reductions of 16% and 38%, respectively, compared with the conventional K-best algorithm implementation, while incurring a signal-to-noise ratio penalty of 0.3 dB at the target bit error rate. Post-synthesis analysis shows that the detector achieves a throughput of 3.29 Gbps at a clock frequency of 137 MHz with a power consumption of 357 mW using a 65-nm CMOS process, which compares favourably with the state-of-the-art implementations in the literature.

Pattern Division Multiple Access: A New Multiple Access Technology for 5G

The anticipated 1000-fold increase in mobile data traffic over the next decade and the explosion of new services and applications pose great challenges for the current orthogonal multiple access (OMA)-based 4G systems. A promising solution to address these challenges is to shift from the currently predominant OMA to non-orthogonal multiple access (NOMA). This article first introduces the principle of the complexity-constrained capacity-achieving NOMA design. Then a non-orthogonal pattern division multiple access (PDMA) scheme is proposed to meet the exponentially growing demand of mobile users for computing and information application services. The key feature of the PDMA scheme is a joint design of transmitter and receiver, which allows low-complexity successive interference cancellation (SIC)-based multi-user detection with substantially improved performance over conventional OMA schemes. More specifically, the patterns of multiple users are judiciously designed so that the data symbols of different users are of appropriate diversity disparity at the symbol level and power disparity at the resource element level. The appropriate disparity in diversity and power can be effectively exploited by the low-complexity SICbased detector to realize the near-perfect cancellation of multi-user interference. Moreover, the PDMA system parameters can be flexibly adjusted to provide different levels of overload, rendering it suitable to meet the diverse traffic requirements in future 5G systems. Link-level simulations illustrate that PDMA is capable of accommodating a 300 percent overload, while it still enjoys transmission reliability close to conventional OMA schemes. The results demonstrated in this article indicate that PDMA can be a promising multiple access technology with low signaling overhead, low latency, and massive connectivity support for 5G.

A Low-Complexity Decoding Algorithm for Coded Hierarchical Modulation in Single Frequency Networks

In this paper, the hierarchical modulation (HM) technique is adopted in a single frequency network (SFN) to provide both global and local information. In order to mitigate the interlayer interference and intercell interference, we develop a low-complexity successive interference cancellation (SIC) algorithm for the coded HM signals in the SFN. The proposed decoding algorithm can be applied to different soft-decision channel coding schemes (e.g., Turbo codes, LDPC codes) under various channel profiles. We analyzed the decoding complexity of the proposed algorithm, and evaluated the bit error rate performance. The simulations show that the new decoding algorithm can offer up to 0.7 dB carrier to noise ratio \((C/N)\) gain compared with the traditional SIC approach under different channel models, while providing the comparable performance (up to 95% decoding complexity savings) with the multilayer iterative decoding approach. The performance evaluation and decoding complexity comparisons indicate that the proposed structured SIC approach offers a good performance-complexity trade-off, especially for the HM-based SFN scenarios.

High-rate groupwise STBC using low-complexity SIC based receiver

In this paper, using diagonal signal repetition with Alamouti code employed as building blocks, we propose a high-rate groupwise space-time block code (GSTBC) which can be effectively decoded by a low-complexity successive interference cancellation (SIC) based receiver. The proposed GSTBC and SIC based receiver are jointly designed such that the diversity repetition in a GSTBC can induce the dimension expansion to suppress interfering signals as well as to obtain diversity gain. Our proposed scheme can be easily applied to the case of large number of antennas while keeping a reasonably low complexity at the receiver. It is found that the required minimum number of receive antennas is only two for the SIC based receiver to avoid the error floor in performance. The simulation results show that the proposed GSTBC with SIC based receiver obtains a near maximum likelihood (ML) performance while having a significant performance gain over other codes equipped with linear decoders.

Joint Design of Groupwise STBC and SIC Based Receiver

In this letter, we propose a simple groupwise space-time block code (GSTBC) which can be easily applied to a large number of transmit antennas and be effectively decoded by a low complexity successive interference cancellation (SIC) based receiver. The proposed GSTBC and SIC based receiver are jointly designed and the diversity repetition in GSTBC is used to induce the dimension expansion that can be exploited by the SIC based receiver to suppress interfering signals as well as to obtain diversity gain. Our proposed scheme provides a near maximum likelihood (ML) performance while keeping a reasonably low complexity at the receiver.

Low complexity successive interference cancellation for MIMO–OFDM systems

AbstractLayered architectures like the V‐BLAST scheme are a promising candidate to exploit the capacity advantages of multiple antenna systems leading to practical wireless communication schemes with very high data rates. The combination with orthogonal frequency division multiplexing (OFDM), called MIMO–OFDM, with per‐antenna‐coding is one of the most likely implementations of these multilayer architectures in frequency selective environments. In this paper, we present a novel, computational efficient implementation of successive interference cancellation (SIC) for coded MIMO–OFDM. It utilises a parallelised version of the Sorted QR Decomposition (SQRD) to achieve the same optimised detection order for all subcarriers, in order to exploit the error correction capability of the forward error correction code within the SIC. In comparison to other schemes known from literature, our approach requires only a fraction of computational complexity with almost the same performance. Copyright © 2007 John Wiley & Sons, Ltd.