Wu Zheng

PAPR reduction with multiple antennas transmission for carrier aggregation

Carrier aggregation (CA) is one technique in Long Term Evolution - Advanced (LTE-A) system, which can extend the bandwidth up to 100MHz and increase the downlink and uplink spectral efficiency. In particular, NxDFT-s-OFDM has been agreed as the uplink bandwidth extension scheme. Nevertheless, the peak-to-average power ratio (PAPR) remains an important issue for user equipment (UE) because it determines the power amplifier (PA) efficiency when multi-carrier transmission is employed. In this paper, a closed-loop component mapping scheme is proposed to solve the PAPR problem caused by the aggregated component carriers (CC). To introduce more diversity gain, a time domain codeword mixing technique is developed to make sure that each Turbo codeword is transmitted through multiple component carriers and multiple antennas. Simulation results show the performance improvements and prove the effective of our proposed approach in terms of PAPR and Block Error Rate (BLER).

Bottleneck-first scheduling for wireless mesh backhaul networks

In this paper, resource allocation for Orthogonal Frequency Division Multiple Access (OFDMA)-based Wireless Mesh Networks (WMNs) is investigated. First, the Even-Odd framework is modified to be better suited for different traffic patterns. Second, the scheduling problem in the modified Even-Odd framework is formulated as a Mixed Integer Quadratically Constrainted Programming (MIQCP), and a heuristic solution is derived. The proposed heuristic solution is motivated from the fact that the bottleneck collision domain throttles the capacity of the networks, and the links in the bottleneck collision domain should be allocated resource carefully to maximize the throughput. The numerical results show that the proposed scheduling scheme can achieve throughput which is over 90% of the nominal capacity and the modified Even-Odd framework improve the end-to-end throughput for asymmetric traffic.