Cross-layer packet scheduling for downlink multiuser OFDM systems

Wang, Junbo; Chen, Huamin; Chen, Ming; Wang, JiangZhou

doi:10.1007/s11432-009-0219-1

Cited by 9 publications

(8 citation statements)

References 19 publications

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“…It can be seen that the expected total rewards of the three policies increase with the increase of the discount factor. This conclusion can directly be derived from Equation (25) or (27). Moreover, compared to the other two policies, the MDP-based handover policy can consistently provide the highest expected total reward per connection for all values of λ.…”

Section: Numerical Resultsmentioning

confidence: 88%

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MDP-based handover policy in wireless relay systems

Dang

Wang

Cao

2012

J Wireless Com Network

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Wireless relay transmission has been considered as a supplementary technology for future wireless communication system, and handover is a key element in wireless relay transmissions to support users' mobility. Handover failure will result in the forced termination of an ongoing call, and a good handover scheme will provide good system performance. This article focuses on the handover decision problem in wireless relay transmission systems. Initially, the architecture of a single-cell relay system is introduced. The handover decision problem is formulated as a Markov decision process (MDP). In the proposed model, a profit function is used to evaluate the quality-of-service of the chosen serving node, and a cost function is used to model processing load and signaling cost. Based on the profit and cost functions, the reward function is formulated. Moreover, the objective is to maximize the expected total reward per connection. The value iteration algorithm is employed to determine the optimal handover policy. Furthermore, the analysis is generalized to multi-cell relay systems. Numerical results show that the proposed MDP-based handover policy is well behaved in wireless relay systems.

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Section: Numerical Resultsmentioning

confidence: 88%

“…Here, each MS is assumed to operate in a pre-assigned orthogonal channel, such as non-overlapping time/frequency slot. This assumption holds for most practical systems such as time division multiple access, frequency division multiple access (FDMA), and OFDMA systems [25]. Therefore, no inter-channel interferences exist among all MSs.…”

Section: System Modelmentioning

confidence: 99%

MDP-based handover policy in wireless relay systems

Dang

Wang

Cao

2012

J Wireless Com Network

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“…orthogonal frequency division multiple access (OFDMA). This not only provides additional flexibility for resource allocation (increasing the capacity), but also enables cross-layer optimization of radio link usage, for example cross-layer packet scheduling [10].…”

Section: Multicarrier Transmissionmentioning

confidence: 99%

A survey of next generation mobile communications research in China

Tian

Zheng

et al. 2011

Chin. Sci. Bull.

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With the rapid development of wireless communication networks, the fourth generation (4G) has emerged to move beyond the limitations of the third generation (3G), with increased bandwidth, enhanced quality of services, and reduced costs of resources. In this paper, we discuss the key technologies of 4G and focus on surveying the ongoing research in 4G communications in China. The 4G technologies under investigation include multicarrier transmission, multiple antenna techniques, carrier aggregation, relays, cognitive radio, distributed antenna systems, network convergence, and network self-optimization. These technologies are the building blocks of 4G and contribute largely to the requirements of International Mobile Telecommunications Advanced (IMT-Advanced). For each technology, its benefits, research topics, and some existing approaches are examined. Finally, we briefly discuss the challenges and future research issues in 4G systems. multicarrier transmission, multiple antenna techniques, carrier aggregation, relay, cognitive radio, distributed antenna system, network convergence, network self-optimization Citation:The limitations of the third generation (3G) and the rapid growth in user demands has called for more advanced and efficient technologies for new generation systems. The upcoming fourth generation (4G) mobile communication systems are expected to solve the still-remaining problems of 3G systems and to provide a wide variety of adaptable services for mobile and nomadic users by using integrated heterogeneous network infrastructure. Based on a comprehensive and secure internet protocol (IP) solution, various services, such as voice, video, broadcasting media, and Internet, will be provided to users with high data rates anytime and anywhere. This is also known as the always best connected concept stating that a user can have the best service connection regardless of time and location.According to the steadily increasing demands and technology developments, wireless communication evolution can be grouped into different generations of networks. Each new generation has brought advances that revolutionized the field of mobile communication. The first generation (1G), initiating commercial mobile voice services with analog techniques, built the basic structure of mobile communications and solved many fundamental problems such as the multiplexing frequency band, roaming across domains, non-interrupted communication in mobile circumstances, and so on. The second generation (2G) of wireless technology, which marked the switching of mobile communication technology from analog to digital, offered higher capacity and lower costs for network operators as well as messages and low-rate data services for users, by using a circuit switch infrastructure. Working under 2G's framework, 2.5G brought the internet into mobile personal communications based on a packet switched radio connection technique. 3G systems, a mixture of packet and circuit-switched networks, are committed to achieving greater network capacity

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“…It can take advantages of the time-varying nature of wireless channels to transmit higher data rate under favorable channel conditions and to reduce throughput as the channel degrades by varying the transmit power, symbol rate, code rate, and their combination. Thus it can provide much higher spectrum efficiency without sacrificing bit error rate (BER) [1][2][3][4][5][6][7]. Adaptive modulation has been applied in numerous wireless communication systems successfully [8][9][10], such as general packet radio service (GPRS), enhanced data rate for GSM Evolution (EDGE), wireless local area networks, advanced personal handy-phone system (PHS), UMTS standards, WCDMA, evolution data optimized (EVDO) technique in third-generation (3G) systems [8,9], etc.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of variable-power adaptive modulation in space-time block coded MIMO diversity systems

Shi

2010

Sci. China Inf. Sci.

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In this paper, the performance analysis of multi-antenna MIMO systems with variable-power (VP) adaptive modulation and space-time coding is presented. The fading gain value is partitioned into a number of regions by which we decide the transmission power according to the region the fading gain falls in. The optimum fading gain region boundaries (switching thresholds) for maximizing spectrum efficiency (SE) under a target BER and average power constraint are derived. It is shown that the Lagrange multiplier in the constrained SE optimization will be unique if the existence condition for multi-antenna systems is satisfied, and is unique for single antenna systems. A practical iterative calculation method based on Steepest Descent Algorithm for finding the Lagrange multiplier is proposed. With the switching thresholds, the closed-form expressions of the SE and average BER, respectively for VP system and constant-power (CP) system are achieved. Simulation results for SE and average BER are in good agreement with the theory analysis. The results show that VP adaptive modulation with space-time coding provides better SE than the counterpart with CP under a target BER and average power constraint. Keywordsadaptive modulation, variable power, space-time block code, constant power, multiple input multiple output (MIMO) CitationYu X B, Shi H B. Performance analysis of variable-power adaptive modulation in space-time block coded MIMO diversity systems.

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Cross-layer packet scheduling for downlink multiuser OFDM systems

Cited by 9 publications

References 19 publications

MDP-based handover policy in wireless relay systems

MDP-based handover policy in wireless relay systems

A survey of next generation mobile communications research in China

Performance analysis of variable-power adaptive modulation in space-time block coded MIMO diversity systems

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