An efficient Relay Station deployment scheme based on the coverage and budget constraints in Multi-hop Relay networks
02 Apr 2015-pp 0124-0128
TL;DR: This work identifies the candidate positions of RS that will achieve maximum system capacity and proposes two algorithms based on coverage and budget constraints to provide a better Quality of Service (QoS) with a minimum deployment cost.
Abstract: Optimum deployment of Relay Station (RS) is considered as the most important issue especially for the users near cell boundary. The Multi hop Relay (MHR) network introduces the RS for the purpose of extended coverage and increased throughput. The main objective of this work is to provide a better Quality of Service (QoS) with a minimum deployment cost. In this paper, we identify the candidate positions of RS that will achieve maximum system capacity. Based on the relay location, we propose two algorithms based on coverage and budget constraints. The simulation results indicate that the proposed algorithms achieved a reasonable coverage ratio within the budget constraint.
Citations
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TL;DR: A flexible four-stage fuzzy logic-based HetNet deployment scheme is proposed, which deploys mix of Macro-e NB, Micro-eNB and relay station (RS) by considering capacity, coverage and cost factors and demonstrates that the proposed scheme is more flexible and offers improved performance in terms of system cost and power ratio.
Abstract: The network capacity has to be maximized to support the ever-increasing data traffic demand. One of the potential outcomes to enhance the network capacity is to enhance the spectral efficiency per unit area by expanding the serving node densities. This is unreasonable on account of present Macro evolved node B (eNB) for which site acquisition is expensive. The idea of heterogeneous network (HetNet) and multi-hop relay (MHR) are extremely prominent in long-term evolution (LTE) standard, where small cells are deployed along with Macro cell. Small cells are more suitable solution for the coverage and traffic issues experienced by Macro cell users. Unfortunately, HetNet deployment is not specified in any of the standards. The network operators have been managing tremendous investments for cellular infrastructures. Because of the high cost and lack of radio resources, a precise and productive HetNet deployment seems uttermost important. In this work, a flexible four-stage fuzzy logic-based HetNet deployment scheme is proposed, which deploys mix of Macro-eNB, Micro-eNB and relay station (RS) by considering capacity, coverage and cost factors. The proposed scheme identifies the required number of eNBs, their types and deployment locations to offer the expected coverage in a cost-effective way. The simulation results demonstrate that our proposed scheme is more flexible and offers improved performance in terms of system cost and power ratio than the conventional HetNet deployment schemes.
23 citations
TL;DR: A linear model that fairly allocates wireless resources among subscribers in 802.16j network is proposed and results show that optimal relays selection scheme do provide a substantial increase of up to 66% in overall network capacity in the fixed WiMAX network.
Abstract: Worldwide Interoperability for Microwave Access network accepts the challenge of last mile wireless access for internet. IEEE 802.16 standard, commercially known as WiMAX provide wireless broadband experience to the end subscribers and challenges many wired solutions like Digital Subscriber Line (DSL) and cable internet. Wireless network has many inherent issues like coverage holes; capacity optimization and mobility are few of them. Adding relays to multi-hop WiMAX IEEE 802.16j network present an effective solution to address them to some extent but this amendment does not elaborate any algorithm regarding the relay selection and narrate no performance guarantees. In this work, we proposed linear model that fairly allocates wireless resources among subscribers in 802.16j network. A relay selection algorithm is also presented to optimally select nodes with higher signal-to-noise ratio as relay station for nodes with lower signal-to-noise ratio objectively maximize overall network capacity. This scheme further extends network coverage area and improves network availability. We also did extensive performance evaluation of the proposed linear model. Results show that optimal relays selection scheme do provide a substantial increase of up to 66% in overall network capacity in the fixed WiMAX network. This improvement is substantial at places where network condition is not optimal. Investigating the problem further leads to the conclusion that the relay selection criterion is the key to achieve maximum network capacity.
2 citations
TL;DR: In this paper , the closed-form expressions for the signal-to-noise ratio (SNR) performance loss and achievable rate of the RIS-aided amplify-and-forward (AF) relay network were derived under the line-of-sight (LoS) channels and Rayleigh channels, respectively.
Abstract: As a new technology to reconfigure wireless communication environment by signal reflection controlled by software, intelligent reflecting surface (IRS) has attracted lots of attention in recent years. Compared with conventional relay system, the relay system aided by IRS can effectively reduce the cost and energy consumption, and significantly enhance the system performance. However, the phase quantization error generated by IRS with discrete phase shifter may degrade the receiving performance of the receiver. To analyze the performance loss caused by IRS phase quantization error, based on the law of large numbers and Rayleigh distribution, the closed-form expressions for the signal-to-noise ratio (SNR) performance loss and achievable rate of the IRS-aided amplify-and-forward (AF) relay network, which are related to the number of phase shifter quantization bits, are derived under the line-of-sight (LoS) channels and Rayleigh channels, respectively. Moreover, their approximate performance loss closed-form expressions are also derived based on the Taylor series expansion. Simulation results show that the performance losses of SNR and achievable rate decrease with the number of quantization bits increases gradually. When the number of quantization bits is larger than or equal to 3, the SNR performance loss of the system is smaller than 0.23dB, and the achievable rate loss is less than 0.04bits/s/Hz, regardless of the LoS channels or Rayleigh channels.
References
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TL;DR: Simulation results show that the proposed schemes can maximize the number of served UE units and the overall throughput of a cell in a realistic multiple-RS-multiple-UE scenario and effectively improve service coverage and system throughput.
Abstract: Relay technologies have been actively studied and considered in the standardization process of next-generation mobile broadband communication systems such as 3GPP LTE-Advanced, IEEE 802.16j, and IEEE 802.16m. This article first introduces and compares different relay types in LTE-Advanced and WiMAX standards. Simulation results show that relay technologies can effectively improve service coverage and system throughput. Three relay transmission schemes are then summarized and evaluated in terms of transmission efficiency under different radio channel conditions. Finally, a centralized pairing scheme and a distributed pairing scheme are developed for effective relay selection. Simulation results show that the proposed schemes can maximize the number of served UE units and the overall throughput of a cell in a realistic multiple-RS-multiple-UE scenario.
670 citations
"An efficient Relay Station deployme..." refers background in this paper
...Using proper deployment of RS, an increased throughput and coverage can be achieved in a cost effective manner [3]....
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TL;DR: Numerical results from a case study show that the selection of the corresponding optimal RS increases the expected end-to-end capacity for individual SSs by 50%, as compared with the method without using relays.
Abstract: This paper examines the IEEE 802.16j multihop relay (MR) technology that improves vehicle-to-infrastructure communications. We study the selection of optimal relay station (RS) for a vehicular subscriber station (SS) that maximizes the end-to-end capacity, assuming that the locations of vehicular SSs are known. By incorporating a highway mobility model, the problem can be formulated into a nonlinear optimization problem and solved for the optimal locations of RSs that guarantee maximal end-to-end capacities to SSs. Numerical results from a case study show that the selection of the corresponding optimal RS increases the expected end-to-end capacity for individual SSs by 50%, as compared with the method without using relays.
118 citations
TL;DR: The throughput performance shows that with the deployment strategy proposed, the IEEE 802.16j network capacity can be tremendously enhanced, especially when hotspots are present in the network.
Abstract: In this paper, we study the relay station (RS) placement strategy in IEEE 802.16j WiMAX networks. Specifically, the impact of RS placement on IEEE 802.16j network performance is analyzed. A throughput maximization RS placement problem is mathematically formulated as a binary integer programming problem. We prove the NP-hardness of the formulated problem. To find the sub-optimal solution to the problem with huge input size, we propose an efficient near-optimal placement solution for IEEE 802.16j WiMAX networks. Simulations on the IEEE 802.16j network performance with our RS placement strategy are conducted. The throughput performance shows that with the deployment strategy we proposed, the IEEE 802.16j network capacity can be tremendously enhanced, especially when hotspots are present in the network.
78 citations
"An efficient Relay Station deployme..." refers methods in this paper
...In [10], a heuristic algorithm is explained for the deployment of RS to find out the number and location of the RSs....
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TL;DR: This paper first models the MCPPR as a particular bicriteria path problem involving an aggregated function of the path and relay costs, as well as a weight function, and considers a variant of this problem which takes into account all three functions separately.
61 citations
"An efficient Relay Station deployme..." refers background in this paper
...Although the deployment cost of RS is less than BS, deploying a large number of RS increases the total budget [6]....
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15 Apr 2008
TL;DR: This paper investigates the optimal relay location aiming to maximize system capacity and considers two relay selection rules for determining whether a two-hop transmission is necessary: signal strength-oriented and throughput-oriented.
Abstract: Relay stations (RSs) are usually used to enhance the signal strength for the users close to the cell boundary. However, transmission through a relay station needs two transmission phases, i.e., one is from the base station to the relay station and the other is from relay station to mobile stations. Thus, relay may also decrease system capacity if two-phase transmission time is considered. As a result, whether or not data are transmitted by one-hop or two-hop transmission should be determined based on both signal strength and throughput. In this paper, we investigate the optimal relay location aiming to maximize system capacity. We consider two relay selection rules for determining whether a two-hop transmission is necessary: signal strength-oriented and throughput-oriented. We find that the signal strength-oriented two-hop transmission may yield even lower system capacity than the one-hop transmission. Based on the throughput-oriented rule, we find that the throughput in the two-hop transmission can be higher than that in the one-hop transmission at some locations. We also identify the optimal relay location that can achieve the highest system capacity.
52 citations