Article

Utility-Optimal Multi-Pattern Reuse in Multi-Cell Networks.

Dept. of Electr. Eng., Univ. of Southern California, Los Angeles, CA, USA
IEEE Transactions on Wireless Communications (Impact Factor: 2.42). 01/2011; 10:142-153. DOI: 10.1109/TWC.2010.110310.091778
Source: DBLP

ABSTRACT Achieving sufficient spatial capacity gain through the use of small cells requires careful consideration of inter-cell interference (ICI) management via BS power coordination coupled with user scheduling inside cells. Optimal algorithms are known to be difficult to implement due to high computation and signaling overhead. This study proposes joint pattern-based ICI management and user scheduling algorithms that are practically implementable. The key idea is to decompose the original problem into two sub-problems in which ICI management is run at a slower time scale than user scheduling. We empirically show that even with such a slow tracking of system dynamics at the ICI management part, the decomposed approach achieves a considerable performance increase compared to conventional universal reuse schemes.

0 Bookmarks
 · 
80 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Fractional frequency reuse (FFR) is an inter-cell interference coordination (ICIC) scheme wherein the whole bandwidth is divided into regions using different frequency reuse factors in orthogonal frequency division multiple access (OFDMA) networks. However, it is hard to achieve the balance of cell-edge and cell-center user throughput in practice as all base stations (BS) are configured with static transmission power for each sub-band in traditional FFR. To solve this problem, a gradient projection based self-optimizing (GPB-SO) algorithm for ICIC is proposed to adjust transmission power of each sub-bands set by exchanging the gradient direction information, aiming to maximize the overall network utility. Furthermore, a closed-form of gradient direction is attained to update the transmission power of each BS in a distributed manner. With the simulation results, it is demonstrated that the proposed algorithm not only provides a better tradeoff between spectrum efficiency and cell-edge user throughput, but also increases the system energy efficiency due to interference reduction.
    Communications and Networking in China (CHINACOM), 2012 7th International ICST Conference on; 01/2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: Greening effect in interference management (IM), which is a technology to enhance spectrum sharing via intelligent BS transmit power control, can be achieved by the fact that even small reduction in BS transmit powers enables considerable saving in overall energy consumption due to their exerting influence on operational powers. In this paper, we study the impact of power sharing policies in IM schemes on cellular network greening, where different spatio-temporal power sharing policies are considered for a fixed system-wide power budget. This study is of great importance in that the pressure on the CO2 emission limit per nation increases, e.g., by Kyoto protocol, which will ultimately affect the power budget of a wireless service provider. We propose optimization theoretic IM frameworks with greening, from which we first develop four IM schemes with different power sharing policies. Through extensive simulations under various configurations, including a real BS deployment in Manchester city, United Kingdom, we obtain the following interesting observations: (i) tighter greening regulation (i.e., the smaller total power budget) leads to higher spatio-temporal power sharing gain than IM gain, (ii) spatial power sharing significantly excels temporal one, and (iii) more greening gain can be achieved as the cell size becomes smaller.
    9th International Symposium on Modeling and Optimization in Mobile, Ad-Hoc and Wireless Networks (WiOpt 2011), May 9-13, 2011, Princeton, NJ, USA; 01/2011
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Small cells such as pico or femto cells are promising as a solution to cope with higher traffic explosion and the large number of users. However, the users within small cells are likely to suffer severe inter-cell interference (ICI) from neighboring base stations (BSs). To tackle this, several papers suggest BS transmit power on/off control algorithms which increase edge user throughput. However, these algorithms require centralized coordinator and have high computational complexity. This paper makes a contribution towards presenting fully distributed and low complex joint BS on/off control and user scheduling algorithm (FDA) by selecting on/off pattern of BSs. Throughput the extensive simulations, we verify the performance of our algorithm as follows: (i) Our FDA provides better throughput performance of cell edge users by 170% than the algorithm without the ICI management. (ii) Our FDA catches up with the performance of optimal algorithm by 88-96% in geometric average throughput and sufficiently small gap in edge user throughput.
    The Journal of Korea Information and Communications Society. 01/2013; 38A(12).