Base Station Selection in Uplink Macro Diversity Cellular Systems with Hybrid ARQ

Abstract

In a cooperative multi-cell network the uplink signal coming from each mobile terminal (MT) is simultaneously demodulated by multiple base stations (BSs). Both backhaul capacity and BS processing capabilities limit the number of demodulating BSs. In order to fit the information exchange among BSs to backhaul resources we minimize the average number of demodulating BSs, under a constraint on the average outage probability. The BS selection problem becomes more complicated when error control configurations as automatic repeat request (ARQ) and hybrid ARQ (HARQ) with chase combining or incremental redundancy are considered. Multi-cell processing is implemented both by decoding the packet at each BS and by a joint decoding among BSs. We first derive the outage probability as a function of the number of cooperating BSs and the error control strategy. A heuristic approach for BS selection is then developed, to find at each frame which BSs perform demodulation and share the information in the backhaul. Lastly, we show that backhaul usage can be reduced up to 64% with respect to an unoptimized solution

Resource allocation for network MIMO systems with HARQ and partial channel knowledge

“…Zennaro et al [10] proposed a local decoding strategy. In their study each cooperating BS attempts to decode the packet transmitted by a subset of MTs independently from the other BSs, i.e., without exchange of information with cooperating BSs.…”

“…The capacity of the macro diversity approach with backhaul constraints has been studied in [9] for the special case of a circular Wiener model. For an MCP scenario where MTs employ hybrid automatic repeat request (HARQ) and transmit at a fixed rate, the minimum number of cooperating BSs required to achieve a target outage probability after a fixed number of HARQ slots has been derived in [10].…”

Optimal resource allocation in distributed broadband wireless communication systems

“…This work considers selection of a subset of the available distributed antennas such that the probability of packet queuing delay is less than a threshold. [6] considers uplink transmission in a distributed BWC system. Again, the objective has been selection of a subset of distributed antennas at each user to keep packet loss probability below a threshold value.…”

“…Again, the objective has been selection of a subset of distributed antennas at each user to keep packet loss probability below a threshold value. In both [5] and [6], locations of the antennas are fixed and the objective function has not been optimized with respect to (wrt) the location of the antennas.…”

“…Then, we determine the optimal location of antennas that minimizes the antenna outage probability. We note that our work is more general compared to [5,6], because it considers multiple types of traffic with different QoS requirements. In relation to optimal placement of antennas, our work is closer to that in [8], but we consider the uplink as opposed to downlink communications, which is more critical due to limited transmit power of the users.…”