Static Inter-Cell Interference Coordination Techniques for LTE Networks: A Fair Performance Assessment (original) (raw)
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Performance evaluation of downlink interference coordination techniques in LTE networks
2010
This paper presents a joint study of several intercell interference coordination strategies considering both static and dynamic approaches, and with different adjustments in their basic parameters. A wide evaluation is presented with special emphasis on the efficiency vs. fairness tradeoff. Besides, additional performance metrics have been considered as enablers of a full understanding of the strengths and weaknesses of each method. Results show that, although spectral efficiency can achieve similar values with proper tuning, certain schemas outperform others in important parameters such as the effectiveness in the utilization of resources. Dynamic semi-centralized approaches appear as an attractive option with an acceptable level of adaptability, moderate complexity and good performance.
2015 7th International Conference on New Technologies, Mobility and Security (NTMS), 2015
Frequency reuse-1 model is required to satisfy the exponential increase of data demands in mobile networks, such as the Long Term Evolution (LTE) of Universal Mobile Terrestrial radio access System (UMTS). However, the simultaneous usage of the same frequency resources in adjacent LTE cells creates inter-cell interference problems, that mainly affect cell-edge users. Inter-Cell Interference Coordination (ICIC) techniques are proposed to avoid the negative impact of interference on system performance. They establish restrictions on resource usage, such as Fractional Frequency Reuse (FFR), and on power allocation such as Soft Frequency Reuse (SFR). In this paper, we classify the existing ICIC techniques, and investigate the performance of reuse-1, reuse-3, FFR, and SFR schemes under various user distributions, and for various network loads. Performance of cell-center and cell-edge users are inspected, as well as the overall spectral efficiency. System level simulations show the advantages and limitations of each of the examined techniques compared to frequency reuse-1 model under different network loads and user distributions, which helps us to determine the most suitable ICIC technique to be used.
Tdx, 2014
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2015 IEEE 81st Vehicular Technology Conference (VTC Spring), 2015
One major concern for operators of Long Term Evolution (LTE) networks is mitigating inter-cell interference problems. Inter-Cell Interference Coordination (ICIC) techniques are proposed to reduce performance degradation and to maximize system capacity. It is a joint resource allocation and power allocation problem that aims at controlling the trade-off between resource efficiency and user fairness. Traditional interference mitigation techniques are Fractional Frequency Reuse (FFR) and Soft Frequency Reuse (SFR). FFR statically divides the available spectrum into reuse-1 and reuse-3 portions in order to protect cell-edge users, while SFR reduces downlink transmission power allocated for cell-center resources to protect vulnerable users in the neighboring cells. However, these static techniques are not adapted to non-uniform user distribution scenarios, and they do not provide guarantees on throughput fairness between user equipments. In this paper, we introduce a non-cooperative dynamic ICIC technique that dynamically adjusts resource block allocation according to user demands in each zone. We investigate the impact of this technique on throughput distribution and user fairness under non-uniform user distributions, using an LTE downlink system level simulator. Simulation results show that the proposed technique improves system capacity, and increases throughput fairness in comparison with reuse-1 model, FFR and SFR. It does not require any cooperation between base stations of the LTE network.
Performance of Decentralized Interference Coordination in the LTE Uplink
2009 IEEE 70th Vehicular Technology Conference Fall, 2009
Interference management techniques like inter-cell interference coordination (ICIC) will play a key role in enabling high spectral efficiency in future wireless OFDMA-based cellular systems. The aim of ICIC is to lower inter-cell interference by coordinating the usage of spectrum resources among neighboring cells. Especially for the cell-edge users, avoiding the reuse of the same resources in neighboring cells yields a significant increase in SINR and thus capacity. In this paper, we consider decentralized ICIC schemes for the uplink of an LTE system in which base stations perform selfish resource allocation decisions. System level simulations in a multi-cell scenario show the convergence of the distributed schemes towards Nash equilibria. The mean cell throughput as well as the 5% CDF user throughput are compared to those achieved by frequency reuse 1 and 3 deployments. The simulation results show that the proposed schemes adapt well to varying uniform and especially non-uniform traffic loads.
Understanding Static Intercell Interference Coordination Mechanisms in LTE
2011
Abstract This work identifies the factors which determine the behaviour of static interference avoidance schemes: SINR distribution shift, MCS mapping, and proportional MCS usage. The work goes on to challenge the common assumption that it is``best''to give resources with a high reuse factor to those at the cell-edge, by showing for a fixed rate service class, that it is best to be greedy and give these resources to those at the cell-centre.
A novel dynamic inter-cell interference coordination technique for LTE networks
2015
Inter-cell interference problems arise in dense frequency reuse networks such as Long Term Evolution (LTE). They have harmful impact on system performance, especially for cell-edge users or users having bad radio conditions. Inter-Cell Interference Coordination (ICIC) schemes aim at mitigating the interference produced by nearby cells to enhance the performance of cell-edge users. ICIC techniques include static frequency reuse schemes and cellcoordinated schemes. In this paper, we propose a semistatic frequency allocation algorithm that exploits evolved-NodeBs communications via X2 interface to mitigate intercell interference. Each cell is divided into two zones: cellcenter and cell-edge. Cell zone satisfaction is tracked, and the unsatisfied zone gets more frequency resource blocks in a distributed manner. The scope of this work is on the downlink of LTE networks using frequency division duplex transmission mode. An LTE downlink system level simulator is chosen to compare the performance of the proposed technique with the frequency reuse-1 model and the fractional frequency reuse technique. Simulation results show that our technique improves throughput cumulative distribution function, achieves a better throughput fairness, and reduces the percentage of unsatisfied users. It is a dynamic technique able to adapt with non-uniform user distributions and traffic demands.
System level evaluation of LTE networks with semidistributed intercell interference coordination
2009
3GPP LTE is the evolution of UMTS which will make possible to deliver high quality multimedia services with an improved user experience. Since Radio Resource Management (RRM) has been recognized as a key point to successfully accomplish this target, the performance evaluation of a multi-cell resource allocation scheme applied to LTE downlink (DL) is presented in this paper. A semi-distributed RRM framework is discussed and evaluated from a system level viewpoint. Detailed link level simulations have also been carried out to properly back up the results.
Proceedings of the Sustainable Research and Innovation Conference, JKUAT Main Campus, Kenya, 2018
The Long-Term Evolution (LTE) mobile/wireless standard was introduced with the motivation that it would offer remarkable improvement to the previous communication standard – Evolved High Speed Packet Access (HSPA+). LTE systems, unlike the earlier standards, tend to utilize the available frequency spectrum in each cell of the network and hence promise to offer higher throughput to the users in the network, better system capacity, lower latency and delay, improved spectral efficiency etc. In order for the standard to effectively meet up with these performance targets, it has to eliminate or minimize the interference on the network. LTE adopts the Orthogonal Frequency Division Multiple Access (OFDMA) method which successfully eliminates the presence of intra-cell interference by enabling the users in each cell to transmit orthogonally. However, the standard still suffers inter-cell interference which could be as a result of two cell-edge users located in two adjacent cells communicati...
Autonomous Schemes for Inter-cell Interference Coordination in the Downlink of LTE Systems
International Journal of Wireless Information Networks, 2014
Inter-cell interference (ICI) is one of the key challenges that limit the performance of Long Term Evolution and Long Term Evolution Advanced cellular systems. One approach to deal with ICI is through interference avoidance. Unlike static avoidance techniques where a-priori frequency planning and/or explicit inter-cell coordination is used, dynamic avoidance techniques rely on adapting its frequency planning and allocation based on the current state of the network. However, this improvement in performance comes with the cost of an increased complexity due to the coordination and alignments needed among the base stations (eNB) to manage and allocate channels among the users. Accordingly, autonomous ICI coordination techniques are receiving much interest among the various interference avoidance techniques. In this paper, we propose an autonomous self-adaptive scheme (SA, for short) for radio resource management and interference coordination. We then extend the proposed scheme to become self-adaptive power-aware (SAPA) in order to optimize and reduce the transmission power of the eNBs. A key feature in the proposed schemes is that all computations are independent of the number of users and cells in the network. This allows the proposed schemes to adapt to networks of any size and with an arbitrary number of users. Extensive simulation confirms that the proposed SA scheme ensures efficient frequency reuse patterns that lead to significant performance improvements in the throughput of the edge users without affecting other users. Moreover, the SAPA scheme achieves significant improvement in the power efficiency, while maintaining the throughput enhancements achieved by the SA scheme for both center and edge users.