We study the sensitivity of multi-user scheduling performance to channel magnitude misreporting in systems with massive antennas. We consider the round-robin scheduler combined with max-min and waterfilling power controls, respectively. We show that user scheduling combined with power allocation, in general, dampens the negative effect of channel misreporting compared to the purely physical layer analysis of channel misreporting without scheduling. We discover several interesting results. First, we observe a periodicity in rate-loss behavior as the number of misreporting users increases. Second, we find that the waterfilling power control is more robust to channel misreporting compared with max-min power control. Third, for homogeneous users with equal average signal-to-noise ratios (SNRs), channel underreporting is harmful but overreporting is beneficial for max-min power control; the opposite impact is found for waterfilling power control. For heterogeneous users with various average SNRs, however, both underreporting and overreporting harm the system for both power control policies, demonstrating the complex interactions across network layers due to channel misreporting.

It is starting to become a big trend in the era of social networking that people produce and upload user-generated contents to the Internet via wireless networks, bringing a significant burden on wireless uplink networks. In this paper, we contribute to designing and theoretical understanding of wireless cache-enabled uplink transmission in a delay-tolerant small cell network to relieve the burden, and then propose the corresponding scheduling policies for the small base station (SBS) with a limited cache size. Specifically, the cache ability introduced by the SBS enables the SBS to eliminate the redundancy among the upload contents from users. This strategy not only alleviates the wireless backhaul traffic congestion from the SBS to a macro base station (MBS) but also improves the transmission efficiency from users to the SBS. We then investigate the scheduling scheme to offload more data traffic under caching size constraint. Finally, numerical results are provided to demonstrate the significant performance gains of the proposed wireless cache-enabled upload network.

The robustness of system throughput with scheduling is a critical issue. In this paper, we analyze the sensitivity of multi-user scheduling performance to channel misreporting in systems with massive antennas. The main result is that for the round-robin scheduler combined with max-min power control, the channel magnitude misreporting is harmful to the scheduling performance and has a different impact from the purely physical layer analysis. Specifically, for the homogeneous users that have equal average signal-to-noise ratios (SNRs), underreporting is harmful, while overreporting is beneficial to others. In under-reporting, the asymptotic rate loss on others is derived, which is tight when the number of antennas is huge. One interesting observation in our research is that the rate loss “periodically” increases and decreases as the number of misreporters grows. For the heterogeneous users that have various SNRs, both underreporting and overreporting can degrade the scheduler performance. We observe that strong misreporting changes the user grouping decision and hence greatly decreases some users' rates regardless of others gaining rate improvements, while with carefully designed weak misreporting, the scheduling decision keeps fixed and the rate loss on others is shown to grow nearly linearly with the number of misreporters.

This paper considers a multi-pair two-way relaying network, where multiple pairs of full-duplex users are served via a full-duplex relay with large-scale antennas under the amplify-and-forward protocol. Based on maximum-ratio combining/maximum-ratio transmission (MRC/MRT) processing, an exact achievable rate expression is derived by utilizing the statistical distribution of the channels to detect the desired signals, with the case of a finite number of relay antennas. We show that the exact expression is a tight lower bound of the ergodic rate. Then we obtain its approximate closed-form, which keeps very close to the exact one, especially in large number of antennas. The proposed approximate expression indicates that increasing the relay antenna number can greatly improve the sum rate. In addition, the optimal transmit powers of the users and the relay are obtained in order to maximize the achievable rate. Moreover, we demonstrate that with very large antenna arrays, the two-way full-duplex relaying scheme outperforms both the one-way full-duplex relaying scheme and the two-way half-duplex relaying scheme. Finally, numerical results are presented to verify the accuracy of the analysis.

In this paper, we consider a multipair amplify-and-forward two-way relay channel, where multiple pairs of full-duplex users exchange information through a full-duplex relay with massive antennas. For improving the energy efficiency, four typical power-scaling schemes are proposed based on the maximum-ratio combining/maximum-ratio transmission (MRC/MRT) and zero-forcing reception/zero-forcing transmission (ZFR/ZFT) at the relay. When the number of relay antennas tends to infinity, we quantify the asymptotic spectral efficiencies and energy efficiencies for the proposed power-scaling schemes. We show that the loop interference can be reduced by decreasing the transmit power under massive relay antennas. Besides, the inter-pair interference and inter-user interference in such systems can also be eliminated in large number of antennas. Moreover, we analytically compare the performance between MRC/MRT and ZFR/ZFT, and describe the impact of the number of user pairs on the spectral efficiency. We also evaluate the energy efficiency performance based on the practical power consumption model, and depict the impact of the relay antenna number on the energy efficiencies for the proposed schemes. Furthermore, we provide the available regions where full-duplex systems can outperform half-duplex systems. Finally, we show that the proposed schemes achieve good performance tradeoffs between the spectral efficiency and the energy efficiency.

In this paper, we consider a one-pair amplify-and-forward relay channel, where two full-duplex users exchange information through a full-duplex relay with a very large number of antennas, while each user only has two antennas. Several power-scaling schemes are proposed based on the maximum-ratio combining/maximum-ratio transmission (MRC/MRT) at the relay. When the number of the relay antennas tends to infinity, we derive and quantify the asymptotic spectral efficiency of the proposed power-scaling schemes. We show that the very large antenna array can significantly reduce the effect of loop interference because of the antenna array gain. Furthermore, the theoretical results indicate that the loop interference can also be reduced by cutting down the transmission power, which is verified by the numerical results. The analytical and numerical results show that the proposed power-scaling schemes can achieve good performance tradeoffs between the spectral efficiency and the energy efficiency.

In this paper, we consider a multi-pair two-way amplify-and-forward relay interference channel, where multiple pairs of full-duplex users exchange information through a full-duplex relay with very large number of antennas, while each user only has two antennas. In order to save the transmission power, four typical power scaling schemes are proposed based on the maximum-ratio combining/maximum-ratio transmission (MRC/MRT) at the relay without the degradation of the performance. When the number of the relay antennas tends to infinity, the asymptotic achievable sum rates based on the proposed power scaling schemes are derived. We show that the very large antenna array can significantly reduce the effect of loop interference because of the antenna array gain. Furthermore, the theoretical results indicate that the loop interference can be reduced by cutting down the transmission power. Besides, the inter-pair interference and the inter-user interference in such systems can also be eliminated in the regime of very large number of antennas. Moreover, we analytically compare the upper bounds of the sum rates for the proposed power scaling schemes and describe the impact of the number of user pairs on the upper bounds.