Jens Berkmann

Multi-layer rate splitting scheme for interference mitigation in tri-sectored wireless networks

In a multi-cell wireless network, cell-edge user equipments (UEs) inevitably suffer from strong interference from adjacent cells which leads to the UE throughput decrease. Contrary to conventional interference mitigation techniques which treat the interference as noise, we propose to use a rate splitting based interference exploitation technique. A novel distributed power allocation algorithm is adopted to optimize the performance. Simulation results show that the multi-layer rate splitting scheme with the proposed power allocation algorithm can approach the best known achievable rate bound of a two-user interference channel and substantially improve the performance of cell-edge UEs in a tri-sectored network.

Inter-cell interference coordination via cooperative rate splitting and scheduling

The current coordinated multi-point transmission schemes require the transmission coordination to avoid the interference. This paper considers the benefit from the rate splitting method, which has been shown to improve the capacity of the interference channel by decoding part of the interference. In this paper, a coordinated multi-point transmission framework based on the cooperative rate splitting scheme is proposed in the Long Term Evolution Advanced system, where a user equipment pair selection algorithm and a cooperative proportional fair scheduling algorithm are newly developed. The simulation results have shown that the coordinated multi-point transmission with cooperative rate splitting can substantially improve the performance of the cell-edge user equipment without or with a slight performance loss at the average rate in a realistic network.

Application of rate splitting transmission scheme for LTE-Advanced systems

In a multi-cell wireless network, an efficient interference mitigation technique is an inevitable part of the current state-of-the-art wireless system. As opposed to conventional interference mitigation techniques which treat the interference as noise, a multi-layer rate splitting scheme can be considered to improve the performance by decoding part of the interference. In this paper, we adapt the multi-layer rate splitting scheme to a Long Term Evolution Advanced framework. Simulation results for two UEs show that the proposed multi-layer rate splitting scheme substantially improves the performance of the cell-edge UE and achieves better fairness between the involved UEs.

Interference mitigation via cooperative rate splitting and scheduling in tri-sectored OFDMA systems

In this paper, a downlink multi-cell orthogonal frequency division multiplexing access (OFDMA) system using the same carrier frequency is studied. The multi-cell interference degrades the performance severely. This paper analyzes the interference mitigation performance of the simple Han-Kobayashi rate splitting scheme in a realistic modeling of the multi-cell system. A cooperative rate splitting scheme is proposed and a closed form optimal power allocation solution is derived. Then, we propose a new scheduling strategy to further improve the performance. Simulation results show that the cooperative rate splitting strategy combined the new scheduling algorithm can get a substantial capacity gain.

Closed loop transmission in EUTRA-LTE system

Closed-loop transmission combined with MIMO (multiple-input multiple-output) technologies have drawn most attentions during development of the LTE (Long Term Evolution) and LTE-Advanced systems. In LTE/LTE-A, the codebook based precoding scheme (termed as PMI-Precoding Matrix Index selection) is deployed for realizing the closed-loop transmission concept. In addition, dynamic transmission mode selection between the spatial multiplexing and transmit diversity, termed as RI (rank indicator) selection, and the adaptive MCS (modulation and coding schemes) selection, realized as CQI (channel quality indicator) selection are also deployed in LTE systems to provide more robust link connection. In this manuscript, the authors focused on the study of selection criteria on the feedback parameters in closed-loop transmission in LTE systems. With joint selection of the PMI, RI and CQI, the authors illustrate an impressive performance improvement given by closed-loop transmission in contrast to open loop transmission and furthermore conclude that the maximum mutual information is one of the optimal criteria for parameters selections.