A study on communication algorithms and test system using ETSI RRS standard for reconfigurable mobile device

Abstract

This dissertation consists of two parts, a study on communication algorithms and a study of test system architecture. The first part proposes a user selection method based on the Signal-to-Interference-plus-Noise-Ratio (SINR) for an MU-MIMO system with limited feedback. In the proposed system, the codebook vector index, the quantization error obtained from the correlation between the measured channel and the codebook vector, and the measured value of the largest singular value are fed back from each user to the base station. In order to maximize the channel capacity in MU-MIMO systems, the user group that is associated with the largest SINR must be selected. Therefore, the received SINR at each user terminal should be computed as accurately as possible at the base station such that the base station can select the user group with the largest SINR. The proposed method not only generates pre-coding vectors that are orthogonal to the pre-coding vectors of the previously selected users and are highly correlated with the codebook vector of each user, but also adopts the quantization error in approximating the SINR, which eventually provides a significantly more accurate SINR than the conventional SINR-based user selection techniques. From computer simulations with the Grassmannian codebook, it has been found that the proposed method enhances the sum rate by at least 2.4 (2.62) bps/Hz compared to conventional SINR-based methods when the numbers of transmit antennas and receive antennas per user terminal are 4 and 1(2), respectively, with 100 candidate users and an SNR=30dB. The second part proposes a test system architecture using the ETSI RRS standard for a reconfigurable mobile device. The conventional test system may be impossible to perform a major update of radios, such as a change of radio specification without hardware replacement, due to an architecture designed to be highly hardware dependent. By enabling joint optimization of software and hardware through the standard interfaces and architecture employing radio virtual machine, the ETSI RRS standard has reconfigurability with a low computational load. In this dissertation, additional operational procedures are defined to apply the ETSI RRS standard architecture to a test system. Also, supporting throughput performance testing of LTE devices with Wi-Fi interference, a prototype with the proposed test system architecture is implemented, and the reference system verifies the operation of the implemented prototype.