Academia.eduAcademia.edu

Outline

Title
Abstract
Key Takeaways
Introduction
Discussion
Conclusions and Future Work
References

Relay architectures for 3GPP LTE-Advanced

Profile image of Kien TruongKien Truong

2009

https://doi.org/10.1155/2009/618787
visibility

…

description

15 pages

link

1 file

Abstract

The Third Generation Partnership Project's Long Term Evolution-Advanced is considering relaying for cost-effective throughput enhancement and coverage extension. While analog repeaters have been used to enhance coverage in commercial cellular networks, the use of more sophisticated fixed relays is relatively new. The main challenge faced by relay deployments in cellular systems is overcoming the extra interference added by the presence of relays. Most prior work on relaying does not consider interference, however. This paper analyzes the performance of several emerging half-duplex relay strategies in interference-limited cellular systems: one-way, two-way, and shared relays. The performance of each strategy as a function of location, sectoring, and frequency reuse are compared with localized base station coordination. One-way relaying is shown to provide modest gains over singlehop cellular networks in some regimes. Shared relaying is shown to approach the gains of local base station coordination at reduced complexity, while two-way relaying further reduces complexity but only works well when the relay is close to the handset. Frequency reuse of one, where each sector uses the same spectrum, is shown to have the highest network throughput. Simulations with realistic channel models provide performance comparisons that reveal the importance of interference mitigation in multihop cellular networks.

Key takeaways
sparkles

AI

  1. Shared relaying offers 90% of the capacity of base station coordination with reduced complexity.
  2. Frequency reuse of 1 maximizes network throughput compared to reuse of 6 in all tested strategies.
  3. Two-way relaying enhances communication efficiency but is hindered by increased interference unless proximity to the mobile is optimized.
  4. One-way relaying provides limited gains over conventional systems due to interference challenges at the cell edge.
  5. The text analyzes performance of half-duplex relay strategies for 3GPP LTE-Advanced in interference-limited environments.

Related papers

Optimized dual relay deployment for LTE-Advanced cellular systems
Mostafa El-khamy

2012 IEEE Wireless Communications and Networking Conference (WCNC), 2012

LTE-Advanced adopts relay deployment to support higher data rates and better coverage, especially at the cell edges which suffer from inter-cell interference. The solution of relaying is attractive because of its low cost and easy deployment. In this paper, we show that deploying just two relays per sector can significantly improve system capacity and coverage. We optimize the geometric deployment of relays that maximizes the spectral efficiency of the worst users or minimize outage. We consider the effects of different backhauling techniques such as wirelessly connected relays or wired radio remote heads. We also investigate the effect of different downlink frame structures and their impact on the system capacity or outage. The paper shows that the proper choice of the geometric deployment, frame structure and backhauling technique of the relays can improve the performance of LTE-Advanced.

View PDFchevron_right
Half-Duplex Relaying in Downlink Cellular Systems
Roy Yates

IEEE Transactions on Wireless Communications, 2000

We compare the performance of half-duplex relays in downlink cellular system against a baseline system without relays. We simulate the performance of (i) a collaborative power addition scheme, where the relay boosts the received power (P-CPA) at the mobile locations, and (ii) a CPA scheme with power control (PC-CPA) at the base station and relays. Evaluations are done in the context of a 19-cell, 57-sector set-up in which each of the served users must be delivered a message. The user messages are taken to have the same size and 90% of users in the network must be served. Improvements over the baseline due to relay deployments are measured in terms of increase in common rate of users as well as power savings in terms of reduction in peak or average power transmitted by base stations. In the CPA schemes with base stations and relays transmitting at full power, the peak power saving is 1.46 dB, alternately, the throughput improvement over a 1 bit/sec/Hz baseline rate is 21%. In the PC-CPA scheme, the peak power saving is 2.6 dB and the average total power in the system can be reduced by 3 dB.

View PDFchevron_right
On the Coverage Extension and Capacity Enhancement of Inband Relay Deployments in LTE-Advanced Networks
Ab Saleh

Journal of Electrical and Computer Engineering, 2010

Decode-and-forward relaying is a promising enhancement to existing radio access networks and is currently being standardized in 3GPP to be part of the LTE-Advanced release 10. Two inband operation modes of relay nodes are to be supported, namely Type 1 and Type 1b. Relay nodes promise to offer considerable gain for system capacity or coverage depending on the deployment prioritization. However, the performance of relays, as any other radio access point, significantly depends on the propagation characteristics of the deployment environment. Hence, in this paper, we investigate the performance of Type 1 and Type 1b inband relaying within the LTE-Advanced framework in different propagation scenarios in terms of both coverage extension capabilities and capacity enhancements. A comparison between Type 1 and Type 1b relay nodes is as well presented to study the effect of the relaying overhead on the system performance in inband relay node deployments. System level simulations show that Ty...

View PDFchevron_right
Coverage enhancement through two-hop relaying in cellular radio systems
David Falconer

2002 IEEE Wireless Communications and Networking Conference Record. WCNC 2002 (Cat. No.02TH8609), 2002

= Digital relaying is a technique that uses certain mobile terminals that have good communication links with the base station to act as relay nodes for those that do not have. With this technique, the signal quality at the destination is expected to improve since the signal only goes through favorable links and, at each intermediate node, the signal is decoded and re-encoded (so that no noise is propagated) before forwarding. One of the major costs of relaying is that additional channels are needed. In this paper, we investigated the effect of using different schemes for selecting channels -among those already used in the adjacent cells -for relaying on performance improvement. Our simulation results show that not only can relaying improve the performance; but also, with power control this improvement is quite insensitive to the channel selection scheme. Furthermore, with small cell radii where there is a potential for high interference level, only a low relay node transmit power is sufficient to improve the system performance significantly.

View PDFchevron_right
Relaying in downlink cellular systems
Roy Yates

2010

The deployment of relays in cellular system has recently been standardized in the WiMAX, IEEE 802.16j standard and is a topic of discussion in the advanced specifications of 3GPP-Long Term Evolution (LTE) . Although commercial relay deployments in cellular systems are not prominent at present, future wireless cellular systems will involve operation with dedicated relays for improving coverage, increasing cell-edge throughput, delivering high data rates and assisting group mobility. The proposed architecture is such that relays would be placed at certain locations (planned or unplanned) in the cell to help in forwarding the message from the base station to the user in the downlink, and from the user to the base station in the uplink. Relays will be more sophisticated than simple repeaters and could perform some digital base band processing to help the destination terminal get better reception. These relays will rely on air interfaces, and hence avoid the considerable back haul costs involving data aggregation and infrastructure costs associated with backbone connectivity. However, there are a lot of open issues that require research to answer. We present some of these issues in the sequel:

View PDFchevron_right
Interference Management Schemes for the Shared Relay Concept
Kien Truong

EURASIP Journal on Advances in Signal Processing, 2011

Sharing a multiantenna relay among several sectors is a simple and cost-effective way to achieving much of the gains of local interference mitigation in cellular networks. Next generation wireless systems, such as ones based on the Third Generation Partnership Projects Long-Term Evolution Advanced, will employ universal frequency reuse to simplify network deployment. This strategy is anticipated to create significant cell-edge interference in the location of the shared relays, thus rendering advanced interference management strategies a necessity. This paper proposes several interference management strategies for the shared relays ranging from simple channel inversion at the relay, to more sophisticated techniques based on channel inversion in combination with partial and full base station coordination in the downlink and uplink. Given that the relay functionality influences total interference, both amplify-and-forward and decode-and-forward type relays are considered throughout. In this context, channel cancelation techniques are investigated for one-way relaying and also the spectrally efficient two-way relaying protocol. Simulations show that strategies based on two-way shared relaying with bidirectional channel inversion at the relay often perform best in terms of total system throughput while one-way techniques are promising when the relay power is low.

View PDFchevron_right
Specific buffer-aided full duplex relaying over LTE advanced networks
L Nithyanandan

International Journal of Mobile Network Design and Innovation, 2017

Full duplex relaying is an emerging technique to transmit and receive simultaneously at the same frequency for enhancing the attainable spectral efficiency in long term evolution advanced (LTE-A) network. The adoption of buffering over relay network outperforms and achieves better outage probability than the conventional relaying. In case of full duplex relaying (FDR) both transmission and reception are happening in same orthogonal channels, the increase in buffer length and higher delay deteriorates the system quality of service (QoS). To achieve both spectral efficiency and QoS, full duplex relay with the separate buffers for receiving and re-transmitting is proposed. The optimal trusted relay selection scheme is incorporated for maximising the security with effective signal-to-interference and noise ratio, which significantly improves the relaying transmission and further Tabu search-based metaheuristic algorithm is used for dealing with the trusted relay selection problem. The performance of three models, i.e., FDR without buffer-aided (conventional FDR), FDR with general buffer and FDR with specific buffer is investigated and compared in terms of outage probability and throughput. The simulation results revealed that the proposed FDR with specific buffer-aided scheme provides better performance compared with other FDR methods.

View PDFchevron_right
Power savings from half-duplex relaying in downlink cellular systems
Roy Yates

2009 47th Annual Allerton Conference on Communication, Control, and Computing (Allerton), 2009

We evaluate the peak and average power savings due to relay deployments in cellular systems via a simulation study. The peak power savings translate to cost reduction in power amplifiers. The average power savings lead to savings in electricity bills. Half-duplex relays are placed one per sector in a 19-cell, 57-sector cellular network. In the baseline case, the base stations control their transmit powers to achieve a common rate among users. When relays are present in the system, optimal powers are found when the relays get the complete message to be relayed to the user. The codebooks at the relays are chosen such that the users obtain a rate corresponding to the sum of the received powers from the base station and the relay. We observe that when power control is employed, the peak power saving is 2.6 dB and the average total power in the system can be reduced by 3 dB.

View PDFchevron_right
On the Multihop Relays with Multiple Antennas for LTE-A
Mario Marques da Silva

In this paper we analyze cooperative communications for broadcast/multicast wireless communication systems based on the LTE-A standard. Multihop relays utilizing the same frequency bands as the base station are considered. These relays are equipped with multiples antennas (MIMO), at least the double of those employed at the base station side. The simulation results show that multihop relays achieve an improvement of power efficiency, while keeping the average coverage and the overall network throughput unchanged. This can be viewed as an energy-efficient wireless transmission technique, which contributes to the implementation of the green cell networks concept, as it allows a reduction in the carbon emission footprint.

View PDFchevron_right
Performance study on cooperative relaying topologies in beyond 3g systems
Rainer Höckmann, Eike Reetz, R. Tönjes

Relaying has been proposed to support users suffering from high shadowing or high interference and therefore being not able to receive high data rates. With adaptive relaying, a higher Modulation and Coding Scheme (MCS) can be used in order to increase the feasible data rate. The investigation of relaying techniques widely has concentrated on information theoretical methods. Instead, this paper focuses on system level simulations to analyse the achievable results within a realistic environment. The question where to locate the Relay Stations is investigated and the achievable system performance is outlined. We show that relaying techniques can improve the median cell throughput and decrease the outage probability. Cooperative relaying results in the lowest outage probability, whereas the introduced concept of Dynamic Resource Relaying (DRR) offers a higher cell throughput. For the investigated LTE (3GPP Long Term Evolution) system with a frequency re-use factor of one, the outage probability can be decreased by using relaying and no further frequency planning is required.

View PDFchevron_right

References (50)

  1. S. Parkvall, E. Dahlman, A. Furuskar, et al., "LTE-advanced- evolving LTE towards IMT-advanced," in Proceedings of the IEEE Vehicular Technology Conference (VTC '08), pp. 1-5, September 2008.
  2. H. Yanikomeroglu, "Cellular multihop communications: infrastructure-based relay network architecture for 4G wire- less systems," in Proceedings of the 22nd Biennial Symposium on Communications, Queen's University, Kingston, Canada, June 2004.
  3. R. Pabst, B. H. Walke, D. C. Schultz, et al., "Relay-based deployment concepts for wireless and mobile broadband radio," IEEE Communications Magazine, vol. 42, no. 9, pp. 80- 89, 2004.
  4. L. Le and E. Hossain, "Multihop cellular networks: potential gains, research challenges, and a resource allocation frame- work," IEEE Communications Magazine, vol. 45, no. 9, pp. 66- 73, 2007.
  5. O. Oyman, N. J. Laneman, and S. Sandhu, "Multihop relaying for broadband wireless mesh networks: from theory to practice," IEEE Communications Magazine, vol. 45, no. 11, pp. 116-122, 2007.
  6. Y.-D. Lin and Y.-C. Hsu, "Multihop cellular: a new architecture for wireless communications," in Proceedings of the 19th Annual Joint Conference of IEEE Computer and Communica- tions Societies (INFOCOM '00), vol. 3, pp. 1273-1282, Tel Aviv, Israel, March 2000.
  7. H. Wu, C. Qiao, S. De, and O. Tonguz, "Integrated cellular and ad hoc relaying systems: iCAR," IEEE Journal on Selected Areas in Communications, vol. 19, no. 10, pp. 2105-2115, 2001.
  8. V. Sreng, H. Yanikomeroglu, and D. Falconer, "Coverage enhancement through two-hop relaying in cellular radio systems," in Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC '02), vol. 2, pp. 881-885, March 2002.
  9. A. Bletsas, A. Khisti, D. P. Reed, and A. Lippman, "A simple cooperative diversity method based on network path selection," IEEE Journal on Selected Areas in Communications, vol. 24, no. 3, pp. 659-672, 2006.
  10. M. Qin and R. S. Blum, "Capacity of wireless ad hoc networks with cooperative diversity: a warning on the interaction of relaying and multi-hop routing," in Proceedings of the IEEE International Conference on Communications, vol. 2, pp. 1128- 1131, May 2005.
  11. G. Scutari, S. Barbarossa, and D. Ludovici, "Cooperation diversity in multihop wireless networks using opportunistic driven multiple access," in Proceedings of the IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC '03), pp. 170-174, June 2003.
  12. E. H. Drucker, "Development and application of a cellular repeater," in Proceedings of the IEEE Vehicular Technology Conference (VTC '88), pp. 321-325, June 1988.
  13. O. Muñoz-Medina, J. Vidal, and A. Agustín, "Linear transceiver design in nonregenerative relays with channel state information," IEEE Transactions on Signal Processing, vol. 55, no. 6, pp. 2593-2604, 2007.
  14. X. Tang and Y. Hua, "Optimal design of non-regenerative MIMO wireless relays," IEEE Transactions on Wireless Commu- nications, vol. 6, no. 4, pp. 1398-1406, 2007.
  15. S. W. Peters and R. W. Heath Jr., "Nonregenerative MIMO relaying with optimal transmit antenna selection," IEEE Signal Processing Letters, vol. 15, pp. 421-424, 2008.
  16. J. N. Laneman, D. N. C. Tse, and G. W. Wornell, "Cooperative diversity in wireless networks: efficient protocols and outage behavior," IEEE Transactions on Information Theory, vol. 50, no. 12, pp. 3062-3080, 2004.
  17. G. Kramer, M. Gastpar, and P. Gupta, "Cooperative strategies and capacity theorems for relay networks," IEEE Transactions on Information Theory, vol. 51, no. 9, pp. 3037-3063, 2005.
  18. D. Chen and J. N. Laneman, "Modulation and demodulation for cooperative diversity in wireless systems," IEEE Transac- tions on Wireless Communications, vol. 5, no. 7, pp. 1785-1794, 2006.
  19. K. Azarian, H. El Gamal, and P. Schniter, "On the achievable diversity-multiplexing tradeoff in half-duplex cooperative channels," IEEE Transactions on Information Theory, vol. 51, no. 12, pp. 4152-4172, 2005.
  20. B. Rankov and A. Wittneben, "Spectral efficient signaling for half-duplex relay channels," in Proceedings of the Asilomar Conference on Signals, Systems and Computers, pp. 1066-1071, November 2005.
  21. B. Wang, J. Zhang, and A. Høst-Madsen, "On the capacity of MIMO relay channels," IEEE Transactions on Information Theory, vol. 51, no. 1, pp. 29-43, 2005.
  22. C. K. Lo, S. Vishwanath, and R. W. Heath Jr., "Rate bounds for MIMO relay channels," Journal of Communications and Networks, vol. 10, no. 2, pp. 194-203, 2008.
  23. C.-B. Chae, T. Tang, R. W. Heath Jr., and S. Cho, "MIMO relaying with linear processing for multiuser transmission in fixed relay networks," IEEE Transactions on Signal Processing, vol. 56, no. 2, pp. 727-738, 2008.
  24. Y. Zhu and H. Zheng, "Understanding the impact of inter- ference on collaborative relays," IEEE Transactions on Mobile Computing, vol. 7, no. 6, pp. 724-736, 2008.
  25. S. W. Peters and R. W. Heath Jr., "The future of WiMAX: multi-hop relaying with IEEE 802.16j," IEEE Communications Magazine, vol. 1, no. 47, 2009.
  26. K. Doppler, C. Wijting, and K. Valkealahti, "On the benefits of relays in a metropolitan area network," in Proceedings of the IEEE Vehicular Technology Conference (VTC '08), pp. 2301- 2305, May 2008.
  27. R. Schoenen, W. Zirwas, and B. H. Walke, "Raising coverage and capacity using fixed relays in a realistic scenario," in Proceedings of the 14th European Wireless Conference (EW '08), pp. 1-6, June 2008.
  28. R. Irmer and F. Diehm, "On coverage and capacity of relaying in LTE-advanced in example deployments," in Proceedings of the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, pp. 1-5, September 2008.
  29. Y. Song, et al., "Relay station shared by multiple base sta- tions for inter-cell interference mitigation," IEEE C802.16m- 08/1436r1, November 2008.
  30. S. Katti, S. Gollakota, and D. Katabi, "Embracing wireless interference: analog network coding," in Proceedings of the ACM Conference on Applications, Technologies, Architectures, and Protocols for Computer Communications (SIGCOMM '07), pp. 397-408, ACM, 2007.
  31. S. J. Kim, N. Devroye, P. Mitran, and V. Tarokh, "Comparison of bi-directional relaying protocols," in Proceedings of the IEEE Sarnoff Symposium (SARNOFF '08), pp. 1-5, April 2008.
  32. A. S. Avestimehr, A. Sezgin, and D. N. C. Tse, "Approxi- mate capacity of the two-way relay channel: a deterministic approach," in Proceedings of the 46th Annual Allerton Confer- ence on Communication, Control, and Computing, pp. 1582- 1589, September 2008.
  33. G. Senarath, et al., "Multi-hop relay system evaluation methodology (channel model and performance metric)," IEEE 802.16j-06/013r3, February 2007.
  34. G. J. Foschini, K. Karakayali, and R. A. Valenzuela, "Coor- dinating multiple antenna cellular networks to achieve enor- mous spectral efficiency," IEE Proceedings: Communications, vol. 153, no. 4, pp. 548-555, 2006.
  35. S. Jing, D. N. C. Tse, J. B. Soriaga, J. Hou, J. E. Smee, and R. Padovani, "Multicell downlink capacity with coordinated processing," EURASIP Journal on Wireless Communications and Networking, vol. 2008, 2008.
  36. M. K. Karakayali, G. J. Foschini, and R. A. Valenzuela, "Net- work coordination for spectrally efficient communications in cellular systems," IEEE Wireless Communications, vol. 13, no. 4, pp. 56-61, 2006.
  37. H. Zhang and H. Dai, "Cochannel interference mitigation and cooperative processing in downlink multicell multiuser MIMO networks," EURASIP Journal on Wireless Communica- tions and Networking, vol. 2004, no. 2, pp. 222-235, 2004.
  38. D. Gesbert, S. G. Kiani, A. Gjendemsjø, and G. E. Øien, "Adaptation, coordination, and distributed resource allocation in interference-limited wireless networks," Proceedings of the IEEE, vol. 95, no. 12, pp. 2393-2409, 2007.
  39. J. Zhang, R. Chen, J. G. Andrews, A. Ghosh, and R. W. Heath Jr., "Networked MIMO with clustered linear precoding," IEEE Transactions on Wireless Communications, vol. 8, no. 4, pp. 1910-1921, 2009.
  40. A. Chakrabarti, A. Sabharwal, and B. Aazhang, "Sensitivity of achievable rates for half-duplex relay channel," in Proceedings of the 6th IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC '05), pp. 970-974, June 2005.
  41. S. Shamai and B. M. Zaidel, "Enhancing the cellular downlink capacity via co-processing at the transmitting end," in Proceed- ings of the IEEE Vehicular Technology Conference (VTC '01), vol. 3, pp. 1745-1749, 2001.
  42. H. Huang and M. Trivellato, "Performance of multiuser MIMO and network coordination in downlink cellular net- works," in Proceedings of the 6th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt '08), pp. 85-90, April 2008.
  43. S. A. Jafar and A. J. Goldsmith, "Transmitter optimization for multiple antenna cellular systems," in Proceedings of the IEEE International Symposium on Information Theory, p. 50, 2002.
  44. M. K. Karakayali, G. J. Foschini, R. A. Valenzuela, and R. D. Yates, "On the maximum common rate achievable in a coordinated network," in Proceedings of the IEEE International Conference on Communications, vol. 9, pp. 4333-4338, June 2006.
  45. E. Biglieri, R. Calderbank, A. Constantinides, A. Goldsmith, A. Paulraj, and H. V. Poor, MIMO Wireless Communications, Cambridge University Press, Cambridge, UK, 2007.
  46. O. Simeone, O. Somekh, Y. Bar-Ness, and U. Spagnolini, "Throughput of low-power cellular systems with collaborative base stations and relaying," IEEE Transactions on Information Theory, vol. 54, no. 1, pp. 459-467, 2008.
  47. O. Somekh, O. Simeone, H. V. Poor, and S. Shamai, "Cellular systems with full-duplex amplify-and-forward relaying and cooperative base-stations," in Proceedings of the IEEE Inter- national Symposium on Information Theory, pp. 16-20, June 2007.
  48. O. Simeone, O. Somekh, Y. Bar-Ness, and U. Spagnolini, "Uplink throughput of TDMA cellular systems with multicell processing and amplify-and-forward cooperation between mobiles," IEEE Transactions on Wireless Communications, vol. 6, no. 8, pp. 2942-2951, 2007.
  49. O. Simeone, O. Somekh, Y. Bar-Ness, H. V. Poor, and S. Shamai, "Capacity of linear two-hop mesh networks with rate splitting, decode-and-forward relaying and cooperation," in Proceedings of the Allerton Conference, Monticello, Ill, USA, Septtember 2007.
  50. O. Somekh, O. Simeone, H. V. Poor, and S. Shamai, "Cellular systems with full-duplex compress-and-forward relaying and cooperative base stations," in Proceedings of the IEEE Interna- tional Symposium on Information Theory, pp. 2086-2090, July 2008.

Related papers

Relaying operation in 3GPP LTE: challenges and solutions
Juan Montojo

IEEE Communications Magazine, 2000

With the ever growing demand of data applications, traditional cellular networks face the challenges of providing enhanced system capacity, extended cell coverage, and improved minimum throughput in a cost-effective manner. Wireless relay stations, especially when operating in a halfduplex operation, make it possible without incurring high site acquisition and backhaul costs. Design of wireless relay stations faces the challenges of providing backward compatibility, minimizing complexity, and maximizing efficiency. This article provides an overview of the challenges and solutions in the design of relay stations as one of the salient features for 3GPP LTE advanced.

View PDFchevron_right
Performance of Amplify-and-Forward and Decode-and-Forward Relays in LTE-Advanced
Ab Saleh

2009 IEEE 70th Vehicular Technology Conference Fall, 2009

Current broadband wireless networks are characterized by large cell sizes. Yet, even in advanced networks, users on the cell edge will face relatively low Signal-to-Interference-plus-Noise-Ratio (SINR). An attractive solution for this problem is provided by multi-hop technologies. In this paper, we consider the performance of full duplex Amplify-and-Forward (AF) and half duplex Decode-and-Forward (DF) Relay Nodes (RNs) from 3G LTE-Advanced perspective. The comparison between AF and DF relaying is important because both approaches are currently under consideration in LTE-Advanced study item in 3GPP. Performance evaluation considers AF RN loop back signal interference and concurrent DF RN transmissions on the access link. Results show that the concurrent transmissions improve the spectral efficiency for DF RN over performing AF RN.

View PDFchevron_right
Effect of Relay Location on Two-Way DF and Af Relay in Lte-A Cellular Networks
Jaafar A Aldhaibani

2012

Wireless multi-hop relay systems are important technologies in mobile communications. These systems ensure high-speed data transfer and extended coverage area at a low cost. This paper investigates the position of a relay problem for the maximum capacity enhancement of a twoway Relay Node (RN) to achieve an efficient and scalable Long Term Evolution-Advanced (LTE-A) wireless network design. The performance of a multi-hop relay network at an optimum position as well as a proposed half-duplex mode with two scenarios is investigated. A single RN for Amplify and Forward (AF) relay is proposed in the first scenario, whereas a Decode and Forward (DF) relay with a multi-hop LTE-A network is proposed in the second scenario. The performance of each scenario is analyzed. The optimum relay position that provides the maximum achievable rate with two-way performance is derived. The numerical results describe the optimum location of AF relay, which is 0.72 of the cell coverage radius, whereas the...

View PDFchevron_right
Effect of relay location on two-way DF and AF relay for multi-user system in LTE-A cellular networks
zaid ali

2013 IEEE Business Engineering and Industrial Applications Colloquium (BEIAC), 2013

Wireless multi-hop relay systems are important technologies in mobile communications. These systems ensure high-speed data transfer and extended coverage area at a low cost. This paper investigates the position of a relay problem for the maximum capacity enhancement of a twoway Relay Node (RN) to achieve an efficient and scalable Long Term Evolution-Advanced (LTE-A) wireless network design. The performance of a multi-hop relay network at an optimum position as well as a proposed half-duplex mode with two scenarios is investigated. A single RN for Amplify and Forward (AF) relay is proposed in the first scenario, whereas a Decode and Forward (DF) relay with a multi-hop LTE-A network is proposed in the second scenario. The performance of each scenario is analyzed. The optimum relay position that provides the maximum achievable rate with two-way performance is derived. The numerical results describe the optimum location of AF relay, which is 0.72 of the cell coverage radius, whereas the DF relay achieves a maximum bit rate when the relay location is at 0.52 from the cell coverage radius.

View PDFchevron_right
Relays-enhanced LTE-Advanced networks performance studies
Mattia Minelli

2011

This paper proposes a study on the performance of multi-hop relays networks. We demonstrate the importance of the relays for coverage and capacity enhancement and study how the number of relays and their position inside the cell impact the performance, and how an efficient relay location scheme can guarantee better performance with less relays per cell. Further we give an estimation of the amount of power per square meter on the ground when relays are used, with respect to traditional network, showing the fundamental role of relays for green networking. We consider the downlink of an LTE-Advanced network, in which all the User Equipments (UE) are supposed to be attached to the eNode-B (eNB) or Relay Node (RN) from which they receive more power. Numerical results are obtained through Monte-Carlo simulations and the performance measures are represented by the average effective Signal to Interference and Noise Ratio (SINR) and the average spectral efficiency.

View PDFchevron_right

Cited by

Interference Management Schemes for the Shared Relay Concept
Kien Truong

EURASIP Journal on Advances in Signal Processing, 2011

Sharing a multiantenna relay among several sectors is a simple and cost-effective way to achieving much of the gains of local interference mitigation in cellular networks. Next generation wireless systems, such as ones based on the Third Generation Partnership Projects Long-Term Evolution Advanced, will employ universal frequency reuse to simplify network deployment. This strategy is anticipated to create significant cell-edge interference in the location of the shared relays, thus rendering advanced interference management strategies a necessity. This paper proposes several interference management strategies for the shared relays ranging from simple channel inversion at the relay, to more sophisticated techniques based on channel inversion in combination with partial and full base station coordination in the downlink and uplink. Given that the relay functionality influences total interference, both amplify-and-forward and decode-and-forward type relays are considered throughout. In this context, channel cancelation techniques are investigated for one-way relaying and also the spectrally efficient two-way relaying protocol. Simulations show that strategies based on two-way shared relaying with bidirectional channel inversion at the relay often perform best in terms of total system throughput while one-way techniques are promising when the relay power is low.

View PDFchevron_right
Design and Analysis of an Interference Cancellation Algorithm for AF, DF and DMF Relay Protocol in Multiuser MIMO Scenario Based on the LTE-Advanced System
Saransh Malik

Wireless Personal Communications, 2014

The analysis and design of relay protocols is a hot issue in 3GPP Long Term Evolution-Advanced. In this paper, we discuss interference cancellation in a multiuser MIMO environment using Amplify-and-Forward (AF), Decode-and-Forward (DF) and De-Modulate-and-Forward (DMF) as relay protocols, and using Thomilson Harashima Precoding and Dirty Paper Coding as precoding techniques, with Zero-Forcing, Minimum Mean Square Error, Successive Interference Cancellation and Ordered Successive Interference Cancellation detection techniques. By using a combination of classical precoding schemes and detection techniques with weighted matrix, we propose a new interference cancellation technique that is capable of cancelling interference. The interference cancellation is managed by AF, DF and DMF relay node protocols and the interference free codeword is transmitted to the selected User Equipment. The proposed algorithm when used with DMF protocol shows best performance, compared to the conventional system or the no-relay system case, it gives

View PDFchevron_right
Improved Buffer-Aided Multi-Hop Relaying with Reduced Outage and Packet Delay in Cognitive Radio Networks
Shakeel Ahmed Alvi

Cognitive radio networks have emerged to exploit optimally the scarcely-available radio spectrum resources to enable evolving 5G wireless communication systems. These networks tend to cater to the ever-increasing demands of higher data rates, lower latencies and ubiquitous coverage. By using the buffer-aided cooperative relaying, a cognitive radio network can enhance both the spectral efficiency and the range of the network; although, this could incur additional end-to-end delays. To mitigate this possible limitation of the buffer-aided relaying in the underlay cognitive network, a virtual duplex multi-hop scheme, referred as buffer-aided multi-hop relaying, is proposed, which improves throughput and reduces end-to-end delays while keeping the outage probability to a minimum as well. This scheme simultaneously takes into account the inter-relay interference and the interference to the primary network. The proposed scheme is modeled as a Markov chain, and Monte Carlo simulations under various scenarios are conducted to evaluate several key performance metrics such as throughput, outage probability, and average packet delay. The results show that the proposed scheme outperforms many non-buffer-aided relaying schemes in terms of outage performance. When compared with other buffer-aided relaying schemes such as max-max, max-link, and buffer-aided relay selection with reduced packet delay, the proposed scheme demonstrated better interference mitigation without compromising the delay performance as well.

View PDFchevron_right
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved