In this paper, we propose fairness-oriented dual-stream multiple-input multiple-output (MIMO) packet scheduling schemes for future multi-antenna packet radio systems. In general, multi-user transmit-receive schemes allow users to be scheduled on different parallel streams on the same time-frequency resource. Based on that, implementations of more intelligent scheduling schemes that are aware of the instantaneous state of the radio channel require utilization of time, frequency and spatial domain resources in an efficient manner. Stemming from the earlier advanced proportional fair (PF) scheduler studies, we extend the developments to dual-stream MIMO packet radios. Furthermore, we investigate the resulting fairness distribution among users together with efficiency in increasing the system capacity in terms of throughput and coverage by simulating practical orthogonal frequency division multiple access (OFDMA) system environment with MIMO functionality in micro and macro cell scenarios. As a concrete example, we demonstrate that by using new multi-user scheduling schemes, significant coverage improvements in the order of 30% can be obtained at the expense of only 14% throughput loss. Furthermore, the user fairness is also greatly increased, by more than 18%, when measured using Jainpsilas fairness index.
"Actually, packet scheduling has been widely studied in recent years. Most of the literatures study proportional fair scheduling (PFS)   , PFS is good for increasing system throughput and user fairness in OFDMA-based systems, however, it can not provide QoS guarantee for different types of traffic. M-LWDF (Modified Largest Weighted Delay First)  and EXP (Exponential)  inject delay consideration into PFS, which aim at QoS guarantee of delay sensitive traffic. "
[Show abstract][Hide abstract] ABSTRACT: In this paper, we propose a packet scheduling algorithm for downlink OFDMA wireless systems in which users have heterogeneous traffic. The proposed scheduling algorithm not only focuses on channel state and fairness but also takes the users' queue length into consideration. With the idea of beta deadline parameter, we convert the delay bound of real-time traffic to date rate domain QoS parameter, and extend the idea for non real-time traffic with the minimum average throughput requirement. According to the subscribers' QoS parameter, we divide the whole band into chunks with different size flexibly. Chunks are allocated to users in accordance with the scheduling rule. Simulation results demonstrate that the proposed scheduling algorithm can acclimatize itself to active user number in the system and the users' requirements for radio resource. Its performance in terms of spectral efficiency, packet loss ratio, and the real-time traffic packets' delay, is better than algorithms with fixed chunk size dividing.
Journal of Networks 06/2012; 7(6). DOI:10.4304/jnw.7.6.956-961
"In the corresponding MIMO (sub-figures (c) and (d)) scenario, we obtain 71% constant coverage gain for the same throughput loss as in previous SIMO case. Compared to the MMPF scheduling principle  or to the power-aware PF in (1), similar coverage gains are obtained, as can be read from the figure. "
[Show abstract][Hide abstract] ABSTRACT: In this paper, we propose fairness-oriented packet scheduling (PS) schemes with power-efficientcontrol mechanism for future packet radio systems. In general, the radio resource managementfunctionality plays an important role in new OFDMA based networks. The control of the networkresource division among the users is performed by packet scheduling functionality based on maximizingcell coverage and capacity satisfying, and certain quality of service requirements. Moreover, multiantennatransmit-receive schemes provide additional flexibility to packet scheduler functionality. Inorder to mitigate inter-cell and co-channel interference problems in OFDMA cellular networks softfrequency reuse with different power masks patterns is used. Stemming from the earlier enhancedproportional fair scheduler studies for single-input multiple-output (SIMO) and multiple-input multipleoutput(MIMO) systems, we extend the development of efficient packet scheduling algorithms by addingtransmit power considerations in the overall priority metrics calculations and scheduling decisions.Furthermore, we evaluate the proposed scheduling schemes by simulating practical orthogonal frequencydivision multiple access (OFDMA) based packet radio system in terms of throughput, coverage andfairness distribution among users. In order to completely reveal the potential of the proposed schemes weinvestigate the system performance of combined soft frequency reuse schemes with advanced powerawarepacket scheduling algorithms for further optimization. As a concrete example, under reducedoverall transmit power constraint and unequal power distribution for different sub-bands, wedemonstrate that by using the proposed power-aware multi-user scheduling schemes, significant coverageand fairness improvements in the order of 70% and 20%, respectively, can be obtained, at the expense ofaverage throughput loss of only 15%.
"[8,10,11,13–18] and the references therein. Using      as starting points for LTE type packet radio systems, it has been reported that frequency domain packet scheduling (FDPS) algorithms are always a compromise between the overall cell throughput and resource fairness among users. Here we propose a modified proportional fair algorithm, which in general offers an attractive balance between cell throughput, coverage and user fairness. "
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