Search

This letter compares pilot-aided phase-shift keyed (PSK) and differential PSK (DPSK) modulation when using new maximum a posteriori joint channel estimation and equalization receivers with frequency-selective fast-fading channels. We conclude that pilot-aided PSK has superior bit-error rate performance in this case. However, at low signal-to-noise ratio, performance is similar, and DPSK is competitive due to reduced receiver complexity. Index Terms--Communication systems, equalizers, fading channels, MAP estimation.

With the rise of cheap small cells in wireless cellular networks, there are new opportunities for third party providers to service local regions via sharing arrangements with traditional operators. In fact, such arrangements may be particularly desirable for large facilities-such as stadiums, universities, and mines-as they already need to cover property costs, and often have fiber backhaul and efficient power infrastructure. In this paper, we propose a network-sharing arrangement between large facilities and traditional operators. Our network-sharing arrangement consists of two aspects: leasing of data access and spectrum from traditional operators; and service agreements with users. As a consequence of the incorporation of the user service agreements into the sharing arrangement, financial as well as physical resource constraints need to be accounted for. This introduces a new dimension into wireless network resource allocation, which requires a new evaluation framework. To this end, we develop a framework based on ruin theory, where the key metric is the probability that the facility is insolvent within a fixed time period. We then investigate the effect of initial capital and physical layer parameters on the ruin probability, which provides insight into the robustness of the network-sharing arrangement to varying conditions. [ABSTRACT FROM AUTHOR]

In this paper, we develop an analytical framework for the initial access (also known as base station (BS) discovery) in a millimeter-wave communication system and propose an effective strategy for transmitting the reference signals (RSs) used for BS discovery. Specifically, by formulating the problem of BS discovery at user equipments (UEs) as hypothesis tests, we derive a detector based on the generalized likelihood ratio test and characterize the statistical behavior of the detector. The theoretical results obtained allow analysis of the impact of key system parameters on the performance of BS discovery, and show that RS transmission with narrow beams may not be helpful in improving the overall BS discovery performance due to the cost of spatial scanning. Using the method of large deviations, we identify the desirable beam pattern that minimizes the average miss-discovery probability of UEs within a targeted detectable region. We then propose to transmit the RS with sequential scanning, using a pre-designed codebook with narrow and/or wide beams to approximate the desirable patterns. The proposed design allows flexible choices of the codebook sizes and the associated beam widths to better approximate the desirable patterns. Numerical results demonstrate the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]