An Optimization Approach to Joint Cell and Power Allocation in Multicell Networks

Abstract

Abstract-Since the seminal paper by Knopp and Humblet that showed that the system throughput of a singlecell system is maximized if only one terminal transmits at a time, there has been a large interest in opportunistic communications and its relation to various fairness measures. On the other hand, in multicell systems there is a need to allocate transmission power such that some overall utility function is maximized typically under fairness constraints. Furthermore, in multicell systems the degree of resource allocation freedom includes the serving cell selection that allows for load balancing and thereby the efficient use of radio resources. In this paper we formulate the joint serving cell selection (link selection) and power allocation problem as an optimization task whose purpose is to maximize either the minimum user throughput or the multicell sum throughput. The max-min problem and a simplified max throughput problem are both NP-hard and we therefore propose heuristic solution approaches. We present numerical results that give new and valuable insights into the trade off between fair and sum throughput optimal joint resource allocation strategies.

Global network coordination in densified wireless access networks through integer linear programming

“…The first approach allows each UE to select its "best" AP in terms of the achieved received signal level, without considering the actual transmission power or interference. Note that this is a usual strategy in cellular networks for cell attachment, and was also proposed in [12]. In mathematical terms, the following rule is applied:…”

“…Network performance was statistically characterized, which differs from our approach, which targets specific coordination strategies and algorithmic solutions. In the context of multi-cell networks, [12] pointed out that the the joint optimization problem of cell (or access point in our context) selection and power allocation is very hard to solve due to its integer non-linear nature. Along those lines, the authors in [12] proposed decoupled heuristic algorithms considering one allocation function at a time, without examining the suboptimality levels of disjoint optimization.…”

“…In the context of multi-cell networks, [12] pointed out that the the joint optimization problem of cell (or access point in our context) selection and power allocation is very hard to solve due to its integer non-linear nature. Along those lines, the authors in [12] proposed decoupled heuristic algorithms considering one allocation function at a time, without examining the suboptimality levels of disjoint optimization. Even when the AP-UE pairings are known, the power optimization sub-problem is difficult to solve, due to its non-convex nature.…”

“…With the newly introduced variables, the minimum SINR per UE expressions are linearized as in (11), and the optimal pairing sub-problem resorts to solving the single ILP problem (12). …”

A survey on power distribution in Wireless Mesh Network

“…Ref. [17] presents a link and power allocation algorithm as an optimization task whose purpose is to maximize either the minimum user throughput or the multicell sum throughput. The authors in [18] study a dynamic channel allocation scheme for array of antennas in OFDMA based systems which offer multicast transmission facility.…”