Opportunistic Sub-channel and Transmit Power Allocation in an OFDMA Based Cognitive Femtocell Network

Abstract

The paper proposes a scheme to minimize the co-tier and cross-tier interference by properly allocating the sub-channels and power among the femtocell users (FUs) in an OFDMA based cognitive femtocell network. An efficient graph coloring based sub-channel allocation scheme is adapted in which the sub-channels in the uplink band of the macrocell are shared by the femtocells dynamically in an opportunistic way through spectrum sensing. A price-based power allocation scheme using game theory is proposed to assign the transmission power among the FUs, whereby the macrocell base-station (MBS) controls the transmission power of the FUs by pricing their resulted interference power levels at the MBS with the constraint that the total interference created at the MBS in each subchannel is kept below a tolerable threshold. The game theoretic approach ensures that no FUs can improve its utility by changing its own transmission power selfishly. The allocation of sub-channels among the FUs is centrally controlled whereas the power allocation is handled in a distributed way which makes the process efficient. Finally, numerical examples are presented to analyze the proposed scheme. The results show that substantial number of FUs with good quality of services can be accommodated in the macrocell reusing the uplink frequency sub-channels and thereby enhancing the throughput and coverage of the network.

Cooperative resource management and power allocation for multiuser OFDMA networks

“…Several dynamic ICIC techniques are introduced [11][12][13]; some of them adjust frequency and power allocation in each cell locally, without any cooperation between eNodeBs. Other techniques depend on the signaling exchange between neighboring eNodeBs.…”

“…Several dynamic ICIC techniques are introduced [11][12][13]; some of them adjust frequency and power allocation in each cell locally, without any cooperation between eNodeBs. For instance, the heuristic power control algorithm introduced in [14] is an autonomous dynamic ICIC technique.…”

Promoting femtocell cooperation through incentive for improving data rate of indoor users in underlay heterogeneous network

“…In [10], the authors have suggested an interference avoidance strategy for two-tier femtocell network in code division multiple access (CDMA)-based system. Many other techniques have been proposed in the literature in order to manage the interference issues in femtocell networks such as using power control [11,12], resource allocation [13,14], using multiple antennas [15][16][17][18] and so on. Along with interference mitigation by power control our work mainly deals with the cooperation of femtocells with macrocell to increase the data rate of indoor macrocell users (MUs).…”

“…This mechanism works jointly along with the pricing‐based power control scheme. The pricing‐based power control part is partially adapted from our previous work [13]. However, the incentive‐based femtocell cooperation jointly with power control is entirely a new approach. The rest of this paper is organised as follows.…”