Capacity Of Heterogeneous Networks Research Articles

Biogeography-based Interference Mitigation Scheme for OFDMA System in Heterogeneous Network

In Heterogeneous Network (HetNet), the small base station such as femtocells are deployed in indoor and multiple business complexes in order to extend the coverage and capacity. The deployment of co-channel (i.e. shared channel) for femtocells along with macrocell induces the severe interference issues. This is because of effects on SINR and thereby capacity become deteriorated. Therefore, this paper investigates the interference mitigation techniques and come out with a proposal to improve the Signal to Interference Noise Ratio (SINR) performance as well as total capacity in Heterogeneous Network (HetNet).The simulation results show that the achieved capacity is maximized than the existing technique.

Enhanced Cell Range Expansion and Radio Resource Allocation for a Better Traffic Offloading in HetNets

Cell range expansion (CRE) is a promising solution to offload macrocells' traffic and improve the radio capacity in heterogeneous network (HetNet). On the other hand, enhanced inter-cell interference coordination (eICIC) techniques are introduced in HetNets to mitigate the severe interference caused between the small cells and the macrocell. In this paper, we present a novel application of the CRE coupled with a new time and frequency domain based eICIC technique. Our approach offers a dynamic radio resource allocation scheme which takes into account the number of femtocells inside the macrocell, the femtocells' loads and the macrocell load. First, we propose a so called FT-CRE scheme which alternates the transmission of the macrocell and the femtocells offering high traffic offloading. Then, a more elaborated scheme called enhanced FT-CRE (eFT-CRE) is presented. In this scheme, the need in traffic offloading is estimated so that time and frequency resources are allocated between the macrocell and the femtocells accordingly. The performance of both proposed FT-CRE and eFT-CRE schemes is evaluated through simulations. The results showed that when FT-CRE scheme is applied, the achieved throughput of the victim macro-users served by femtocells which apply the CRE is increased by 6 times as compared to a common application of CRE technique based on time domain multiplexing eICIC only. The outage probability of these victim macro-users is also significantly decreased. More importantly, the eFT-CRE scheme reveals more effective in terms of total achieved throughput in the system, the outage probability and energy efficiency at the macrocell.

Capacity analysis of LTE-Advanced HetNets with reduced power subframes and range expansion

Abstract The use of reduced power subframes in LTE Rel. 11 can improve the capacity of heterogeneous networks (HetNets) while also providing interference coordination to the picocell-edge users. However, in order to obtain maximum benefits from the reduced power subframes, setting the key system parameters, such as the amount of power reduction, carries critical importance. Using stochastic geometry, this paper lays down a theoretical foundation for the performance evaluation of HetNets with reduced power subframes and range expansion bias. The analytic expressions for average capacity and 5th percentile throughput are derived as a function of transmit powers, node densities, and interference coordination parameters in a two-tier HetNet scenario and are validated through Monte Carlo simulations. Joint optimization of range expansion bias, power reduction factor, scheduling thresholds, and duty cycle of reduced power subframes is performed to study the trade-offs between aggregate capacity of a cell and fairness among the users. To validate our analysis, we also compare the stochastic geometry-based theoretical results with the real macro base station (MBS) deployment (in the city of London) and the hexagonal grid model. Our analysis shows that with optimum parameter settings, the LTE Rel. 11 with reduced power subframes can provide substantially better performance than the LTE Rel. 10 with almost blank subframes, in terms of both aggregate capacity and fairness.

Offloading Performance of Range Expansion in Picocell Networks: A Stochastic Geometry Analysis

Range Expansion (RE) can improve the capacity of heterogeneous networks by increasing the coverage of low power nodes like picocells. So far, however, there have been limited results on quantifying the performance of range expansion and the effect of Range Expansion Bias (REB). To address these issues, using stochastic geometry, we propose a practical load-aware model in which users' minimum throughput requirements and Base Station (BS) load are taken into account. Furthermore, we get a closed-form expression for the outage probability in the heterogeneous network with RE. Compared to previous models which assume all BSs are always fully loaded, the proposed model is more reasonable for lightly-loaded networks. Additional, our results reveal the offloading benefits of RE and provide insights into the settings of system parameters such as REB.

Optimal power allocation for heterogeneous network capacity maximization

We investigate the optimal joint power allocation in Heterogeneous Networks (HetNets) to maximise its capacity. Considering frequency reuse in the network, we study two power-constraint cases, i.e., per-cell power constraint case and per-tier power constraint case. We formulate the capacity maximization problem by allowing each subcarrier of Marco eNodeB (MeNB) to be shared by users from multiple Picos. We mathematically demonstrate that the optimal power allocation in the per-cell power constraint case has a remarkably simple nature: each Pico transmits to its user with maximum power, while MeNB either selects only one user to jointly transmit with maximum power or does not transmit to any user. In the per-tier power constraint case, the difference is that the power allocation between two Picos takes the form of water-filling. Numerical results verify that our proposed schemes outperform the conventional interference coordination schemes.

Peer-to-Peer Based Multimedia Distribution Service

Recently, there are many research interests in providing efficient and scalable multimedia distribution service. However, stringent quality-of-service (QoS) requirements for media distribution, as well as dynamically changing and heterogeneous network capacity in today's best effort Internet, bring many challenges. In this paper, we introduce a novel framework for multimedia distribution service based on peer-to-peer (P2P) networks. A topology-aware overlay is proposed in which hosts self-organize into groups. End hosts within the same group have similar network conditions and can easily collaborate with each other to achieve QoS awareness. In order to improve media delivery quality and provide high service availability, we further propose two distributed heuristic replication strategies, intergroup replication and intragroup replication, based on this topology-aware overlay. Specifically, intergroup replication is aimed to improve the efficiency of media content delivery between the group where a request is issued and the group where the content is stored. Also, intragroup replication is targeted at improving the availability of the content. Extensive simulation results show that the latency in our proposed architecture is 20% less than that of the FreeNet and 50% less than that of the randomly replication system. Simulation results also show that the video quality in our system is much better than that in the other two systems. Our P2P-based approach is also distributed, scalable, cost effective, and aware of the performance.