Conference Paper

Spectral Efficiency and Fairness for Opportunistic Round Robin Scheduling

Norwegian University of Science and Technology, Dept. of Electronics and Telecommunications, 7491 Trondheim, Norway, email:
DOI: 10.1109/ICC.2006.254803 Conference: Communications, 2006. ICC '06. IEEE International Conference on, Volume: 2
Source: IEEE Xplore


In this paper we analyze the Opportunistic Round Robin (ORR) scheduling algorithm [1], [2]. This algorithm is able to exploit multiuser diversity (MUD) and at the same time provide short-term fairness between the users in a wireless cellular network. We analyze the spectral efficiency and the fairness for two scenarios. In the first scenario all the users have the same average carrier-to-noise ratios (CNR) and for the second scenario the users have different average CNRs. For the first scenario the absolute MUD is exploited while we exploit the so-called relative MUD between the users for the second scenario. The advantages and disadvantages of the different ORR implementations are highlighted by analyzing plots of our closed-form expressions.

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Available from: Geir E. Øien, Nov 24, 2014
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    • "The ORR scheduling algorithm can be combined with maximum NSNR scheduling to achieve higher throughput than ORR, by scheduling the user with highest NSNR. This algorithm is denoted as the normalized ORR (N-ORR) [11] "
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    ABSTRACT: In the design of wireless scheduling policies, the fairness criterion plays an important role in upgrading the performance of network. This paper concentrates on how the channel-aware opportunistic scheduler can improve both throughput and fairness in cellular wireless networks. In order to improve the fairness, we propose an adaptive fair scheduling algorithm by using fuzzy logic model. Proposed scheduler operates on Time Division Multiple Access (TDMA) fashion and calculates the priority index of each user according to channel quality fed back and fairness of channel assignment. We evaluate its performance via statistical simulations. The obtained results show that our strategy can improve the fairness but at the expense of slight throughput loss compared to well-known opportunistic scheduling methods.
    IEEE 8th International Conference on Application of Information and Communication Technologies (AICT),, Astana; 10/2014
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    • "On the other hand, the well-known round-robin scheduling [9] maximizes the system fairness by selecting a user arbitrarily regardless of its channel conditions. Proportional fair [19] and opportunistic round-robin [22] are two other popular scheduling schemes that lie in between the two extremes in terms of throughput and fairness trade-off. "
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    ABSTRACT: Base station (BS) sleeping has emerged as a viable solution to enhance the overall network energy efficiency by inactivating the underutilized BSs. However, it affects the performance of users in sleeping cells depending on their BS association criteria, their channel conditions towards the active BSs, and scheduling criteria and traffic loads at the active BSs. This paper characterizes the performance of cellular systems with BS sleeping by developing a systematic framework to derive the spectral efficiency and outage probability of downlink transmission to the sleeping cell users taking into account the aforementioned factors. In this context, we develop a user association scheme in which a typical user in a sleeping cell selects a BS with \textbf{M}aximum best-case \textbf{M}ean channel \textbf{A}ccess \textbf{P}robability (MMAP) which is calculated by all active BSs based on their existing traffic loads. We consider both greedy and round-robin schemes at active BSs for scheduling users in a channel. Once the association is performed, the exact access probability for a typical sleeping cell user and the statistics of its received signal and interference powers are derived to evaluate the spectral and energy efficiencies of transmission. For the sleeping cell users, we also consider the conventional \textbf{M}aximum \textbf{R}eceived \textbf{S}ignal \textbf{P}ower (MRSP)-based user association scheme along with greedy and round-robin schemes at the BSs. The impact of cell-zooming is incorporated in the derivations to analyze its feasibility in reducing the coverage holes created by BS sleeping. Numerical results show the trade-offs between spectral efficiency and energy efficiency in various network scenarios. The accuracy of the analysis is verified through Monte-Carlo simulations.
    IEEE Transactions on Wireless Communications 01/2014; 13(10). DOI:10.1109/TWC.2014.2336249 · 2.50 Impact Factor
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    • "The simple TDMA scheme which uses round-robin scheduling, which we call round-robin (RR) scheme, provides the highest short-term fairness when the time slots are allocated in rounds of K time slots, where K is the number of SNs [13]. Then, the scheduled SNs do not have to contend for the shared medium nor worry about packet collisions since only the owner of the time slot is allowed to transmit a packet. "
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    ABSTRACT: We consider a wireless sensor network that comprises a single hop between the sensor nodes and the central controller node with multiple antennas. In this system model, we concentrate on the single-beam opportunistic communication and propose two novel packet transmission schemes that can perform multiuser diversity gain based on the signal-to-noise ratio (SNR) and the normalized SNR (NSNR) measurements at the sensor nodes with single antenna. The main objective of the multiuser diversity is to increase the total throughput over the fast fading channels. Proposed schemes are based on the principle of cross-layer design that integrates with physical layer characteristics of wireless channel and medium access control (MAC) layer characteristics of network. In our design, we assume that the sensor nodes know only their own channels to the controller node and the packet transfer from the sensor nodes to the controller node is initiated when the channel quality of any node exceeds the predefined threshold at the current time slot. To determine the optimum threshold, we maximize the probability of successful packet transmission where only one sensor node transmits its packet in one time slot under the simplified collision model. Simulation results are demonstrated to compare the performance of the proposed schemes in terms of throughput, energy efficiency, and fairness. The obtained results show that the presented opportunistic strategy can be used to improve the network throughput.
    International Journal of Distributed Sensor Networks 09/2012; 2012. DOI:10.1155/2012/541258 · 0.67 Impact Factor
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