| 1. |
- Mayer, Zoltán, et al.
(författare)
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On the Impact of Control Channel Reliability on Coordinated Multi-Point Transmission
- 2014
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Ingår i: Eurasip Journal on Wireless Communications and Networking. - : Springer Science and Business Media LLC. - 1687-1499 .- 1687-1472. ; 28
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Tidskriftsartikel (refereegranskat)abstract
- In the heterogeneous networks (HetNets), co-channel interference is a serious problem. Coordinated multi-point (CoMP) transmission has emerged as a powerful technique to mitigate co-channel interference. However, all CoMP techniques rely on information exchange through reliable control channels, which are unlikely to be available in HetNets. In this paper, we study the effect of unreliable control channels, consisting of the access links and backhaul links, on the performance of CoMP. A control channel model is introduced by assigning link failure probability (LFP) to backhaul and access links for the cooperative clusters. Three CoMP architectures, namely the centralized, semi-distributed and fully distributed are analyzed. We investigate the probability of deficient control channels reducing quality of service, and impeding transmission. General closed-form expressions are derived for the probability of a cooperative transmission node staying silent in a resource slot due to unreliable control links. By evaluating the average sum rate of users within a CoMP cluster, we show that the performance gains offered by CoMP quickly diminish, as the unreliability of the control links grows.
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| 2. |
- Papadogiannis, Agisilaos, 1982, et al.
(författare)
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Pass it on: Advanced Relaying Concepts and Challenges for Networks Beyond 4G
- 2014
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Ingår i: IEEE Vehicular Technology Magazine. - 1556-6080 .- 1556-6072. ; 9:2, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- Relay nodes (RNs) will be a key feature of future wireless networks. RNs can extend coverage, increase network capacity, and provide more uniform quality-of-service (QoS) across the cell area in a cost-effective manner. Therefore, not surprisingly, relaying techniques have attracted a significant amount of attention from the wireless industry and standards. The Third-Generation Partnership Project (3GPP) release 10 has considered RNs that act as base stations (BSs), known as type-1 RNs, aiming only for coverage extension. However, RNs can be employed in different ways, and several challenges have to be addressed to attain the theoretical gains. This article presents an overview of the relaying concepts related to the 3GPP long-term evolution (LTE) road map, i.e., concepts related to type-1, type-2, and moving RNs. The implementation challenges are outlined, and a number of promising solutions for each RN type are discussed. More specifically, for type-1 RNs, this article focuses on the allocation of resources to the backhaul and access links. For type-2 RNs, the focus is on designing distributed hybrid automatic repeat request (HARQ) protocols that involve RNs. Moving RNs are presented as an efficient solution to the ever-growing demand for wireless broadband by vehicleborne users. Overall, the presented relaying concepts and solutions can significantly improve the user experience and can play an important role in the future.
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