Transmission Schemes Based on Sum Rate Analysis in Distributed Antenna Systems

Abstract

In this paper, we study single cell multi-user downlink distributed antenna systems (DAS) where antenna ports are geographically separated in a cell. First, we derive an expression of the ergodic sum rate for the DAS in the presence of pathloss. Then, we propose a transmission selection scheme based on the derived expressions which does not require channel state information at the transmitter. Utilizing the knowledge of distance information from a user to each distributed antenna (DA) port, we consider the optimization of pairings of DA ports and users to maximize the system performance. Based on the ergodic sum rate expressions, the proposed scheme chooses the best mode maximizing the ergodic sum rate among mode candidates. In our proposed scheme, the number of mode candidates are greatly reduced compared to that of ideal mode selection. In addition, we analyze the signal to noise ratio cross-over point for different modes using the sum rate expressions. Through Monte Carlo simulations, we show the accuracy of our derivations for the ergodic sum rate. Moreover, simulation results with the pathloss modeling confirm that the proposed scheme produces the average sum rate identical to the ideal mode selection with significantly reduced candidates.

Energy- and Spectral-Efficiency Tradeoff for Distributed Antenna Systems with Proportional Fairness

“…Distributed antenna system (DAS) has been introduced as a promising candidate for the next generation wireless communication systems [17]- [20] due to the advantages of increasing capacity, improving the link reliability, and extending the coverage. Different from a traditional collocated antenna system (CAS) where all antennas of a base station (BS) are collocated at the center of a cell, remote access units (RAUs) in the DAS are placed at different locations in a cell and connected to a baseband processing unit (BPU) through optical fibers.…”

Energy Efficient Power Allocation for Distributed Antenna System over Shadowed Nakagami Fading Channel

“…Distributed antenna system (DAS) has emerged as a promising technology for future wireless communications due to its advantage of enhancing the system capacity, improving the signal quality and reducing the power [1][2][3]. In DAS, the remote antennas (RAs) are separated geographically and connected to a central control module via dedicated wires, fiber optics, or an exclusive radio frequency link [3].…”

“…In DAS, the remote antennas (RAs) are separated geographically and connected to a central control module via dedicated wires, fiber optics, or an exclusive radio frequency link [3]. Traditionally, the spectral efficiency (SE) has been used to measure the efficiency of a communication system.…”

Timing Acquisition with Cooperation of Two Distributed Receive Antennas over Flat-Fading Channels

“…However, the potential advantages of using multiple antennas cannot realize for centralized antenna systems (CAS) due to the co-located placement of antennas [1] [2]. Relative to the CAS, the distributed antenna systems (DAS) presents many advantages, e.g., expanding coverage and increasing sum rates by having distributed antenna ports throughout a cell [2]- [4]. As the key technology of the next generation wireless system, the DAS has been attracting worldwide research interests [5] [6].…”