| 1. |
- Kim, Sumin, et al.
(författare)
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Joint Link Adaptation and User Scheduling With HARQ in Multicell Environments
- 2016
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Ingår i: IEEE Transactions on Vehicular Technology. - : IEEE. - 0018-9545 .- 1939-9359. ; 65:3, s. 1292-1302
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Tidskriftsartikel (refereegranskat)abstract
- Intercell interference (ICI) is one of the most critical factors affecting performance of cellular networks. In this paper, we investigate a joint link adaptation and user scheduling problem for a multicell downlink employing hybrid automatic repeat request (HARQ) techniques, where the ICI exists among cells. We first propose an approximation method on aggregated ICI for analyzing an effective signal-to-interference-and-noise ratio (SINR) with the HARQ technique at users, which is known as identical path-loss approximation (IPLA). Based on the proposed IPLA, we propose a transmission rate selection algorithm maximizing an expected throughput at each user. We also propose a simple but effective cross-layer framework jointly combining transmission rate adaptation and user scheduling techniques, considering both HARQ and ICI. It is shown that the statistical distribution of the effective SINR at users based on the IPLA agrees well with the empirical distribution, while the conventional Gaussian approximation (GA) does not work well in the case that dominant ICIs exist. Thus, IPLA enables base stations (BSs) to choose more accurate transmission rates. Furthermore, the proposed IPLA-based cross-layer policy outperforms existing policies in terms of both system throughput and user fairness.
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| 2. |
- Kim, Su Min, et al.
(författare)
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Effects of Heterogenous Mobility on Rate Adaptation and User Scheduling in Cellular Networks With HARQ
- 2013
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Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 62:6, s. 2735-2748
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate the effects of heterogeneous mobility on rate adaptation and user scheduling in cellular networks with hybrid automatic repeat request (HARQ). To this end, we first show the performance tradeoff between two extreme scheduling criteria: retransmission-oriented scheduling (ROS) and mixed scheduling (MS) criteria over time-correlated Rayleigh fading channels. Then, we propose an ROS-based joint rate adaptation and user scheduling (JRAUS) policy for cellular networks and compare it with the conventional and reference JRAUS policies. We also evaluate the system-level performance of the proposed ROS-based JRAUS policy in various user distribution and mobility scenarios. In particular, in an asymmetric user distribution and heterogeneous mobility scenario, which is the most general one in practice, the proposed JRUAS policy yields a throughput gain of 49% and a fairness gain of 155% over the conventional JRAUS policies. In this paper, we find that the rate adaptation is significant not only in a single point-to-point link but in multiuser systems with heterogeneous mobility as well.
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| 3. |
- Shin, Won-Yong, et al.
(författare)
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Opportunistic Network Decoupling with Virtual Full-Duplex Operation in Multi-Source Interfering Relay Networks
- 2017
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Ingår i: IEEE Transactions on Mobile Computing. - : IEEE Computer Society. - 1536-1233 .- 1558-0660. ; 16:8, s. 2321-2333
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Tidskriftsartikel (refereegranskat)abstract
- We introduce a new achievability scheme, termed opportunistic network decoupling (OND), operating in virtual full-duplex mode. In the scheme, a novel relay scheduling strategy is utilized in the K x N x K channel with interfering relays, consisting of K source-destination pairs and N half-duplex relays in-between them. A subset of relays using alternate relaying is opportunistically selected in terms of producing the minimum total interference level, thereby resulting in network decoupling. As our main result, it is shown that under a certain relay scaling condition, the OND protocol achieves K degrees of freedom even in the presence of interfering links among relays. Numerical evaluation is also shown to validate the performance of the proposed OND. Our protocol basically operates in a fully distributed fashion along with local channel state information, thereby resulting in relatively easy implementation.
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| 4. |
- Su Min, Kim, et al.
(författare)
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On the link adaptation and user scheduling with HARQ in the presence of inter-cell interference
- 2013
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Ingår i: Communications (ICC), 2013 IEEE International Conference on. - 9781467331227 ; , s. 6261-6265
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Konferensbidrag (refereegranskat)abstract
- In this paper, we investigate both link adaptation and user scheduling for an HARQ-based multi-user system in downlink multi-cell environments with inter-cell interference (ICI). First, we analyze two approximation methods on the ICI terms for optimal rate selection. One is a conventional well-known Gaussian approximation (GA) and the other is our proposed identical path-loss approximation (IPLA). Thereafter, we propose a baseline procedure for both the link adaptation and user scheduling. Then, we introduce three conventional policies and our proposed IPLA-based policy. Finally, through system-level simulations, the proposed IPLA-based policy is evaluated in terms of system throughput. Numerical results show that the traditional GA is not accurate any more in the HARQ-based multi-user system with some dominant ICIs. Instead of the GA, our proposed IPLA-based policy achieves more accurate rate selection and higher system performance.
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