Xinwei Yue

Advanced IDD receiver for PDMA uplink system

The anticipated 1000 fold increase in traffic demand over the next decade and the explosion of new services and applications, such as the internet of things (IoT), pose great challenges for the current 4G mobile network. Pattern division multiple access (PDMA), as a novel non-orthogonal multiple access scheme, has been proposed recently to address these challenges. The performance of PDMA uplink system mainly depends on the receiver algorithm. The conventional message pass algorithm (MPA) cannot fully exploit the benefits of the coded PDMA system. In this paper, we devise an advanced receiver via iterative detection and decoding (IDD) algorithm which fully exploits coding potentials and diversity gains of the PDMA. The simulation results show that IDD based advanced receiver obtains a performance improvement about 1.6 dB at block error rate (BLER) of 0.01 for 300% overload compared with the MPA based approach.

Exploiting Full/Half-Duplex User Relaying in NOMA Systems

In this paper, a novel cooperative non-orthogonal multiple access (NOMA) system is proposed, where one near user is employed as decode-and-forward relaying switching between full-duplex (FD) and half-duplex (HD) mode to help a far user. Two representative cooperative relaying scenarios are investigated insightfully. The first scenario is that no direct link exists between the base station (BS) and far user. The second scenario is that the direct link exists between the BS and far user. To characterize the performance of potential gains brought by the FD NOMA in two considered scenarios, three performance metrics outage probability, ergodic rate, and energy efficiency are discussed. More particularly, we derive new closed-form expressions for both exact and asymptotic outage probabilities as well as delay-limited throughput for two NOMA users. Based on the derived results, the diversity orders achieved by users are obtained. We confirm that the use of direct link overcomes zero diversity order of far NOMA user inherent to FD relaying. In addition, we derive new closed-form expressions for asymptotic ergodic rates. Based on these, the high signal-to-noise ratio (SNR) slopes of two users for FD NOMA are obtained. Simulation results demonstrate that: 1) the FD NOMA is superior to the HD NOMA in terms of outage probability and ergodic sum rate in the low SNR region; and 2) in delay-limited transmission mode, the FD NOMA has higher energy efficiency than the HD NOMA in the low SNR region; However, in delay-tolerant transmission mode, the system energy efficiency of the HD NOMA exceeds the FD NOMA in the high SNR region.

Outage performance of full/half-duplex user relaying in NOMA systems

This paper investigates the performance of cooperative non-orthogonal multiple access (NOMA) systems, where one near user works as a decode-and-forward (DF) full-duplex (FD) or half-duplex (HD) relaying to help far user. Two cooperative relay scenarios are considered insightfully. 1) The first scenario is that no direct link exists between the base station (BS) and the far user; and 2) The second scenario is that direct link exists between the BS and the far user. To characterize the performance of FD NOMA in two considered scenarios, new closed-form expressions for both exact and asymptotic outage probability as well as delay-limited throughput are derived for each NOMA user. Based on the analytical results derived, the diversity orders achieved by users are obtained. It is confirmed that the use of the direct link overcomes the zero diversity order of far NOMA user inherent to FD relaying. Simulation results demonstrate that the outage performance of FD NOMA is superior to HD NOMA at low SNR region rather than at high SNR region.

Link Performance Estimation Technique for PDMA Uplink System

Pattern division multiple access (PDMA) is a promising non-orthogonal multiple access scheme for the fifth generation mobile communication system. Link performance estimation technique is the key to ensure accurate performance evaluation of the PDMA uplink system. Although the belief propagation (BP) receiver with near-optimal performance is normally considered for PDMA uplink system, it remains a big challenge for the estimation of the link performance for the PDMA uplink system with the BP receiver. In this paper, we first propose a novel link performance estimation technique for the PDMA uplink system with the BP receiver. The performance of the BP receiver is estimated by utilizing the genie-aided interference cancellation receiver as an upper bound with a single fitting parameter. Then, we provide a simple search process of finding the fitting parameter. Finally, the simulation results show that the proposed method achieves greater link performance estimation accuracy over the conventional method in the PDMA uplink evaluation.