Performance study of mobile WiMAX network with changing scenarios under different modulation and coding

This paper presents RA-WF 2Q+, a radio-aware version of the well-known WF 2Q+ scheduler, tailored for the downlink traffic of a WiMAX system. With respect to WF 2Q+, the proposed scheduler introduces the number of slots in the downlink frame as a parameter of the sharing decision process. This solution permits taking into account the information on the radio channel quality experimented by each user and, at the same time, exploiting the well-known features of WF 2Q+. The simulation study comparing the performance of the proposed scheduler with those of other well-known scheduling algorithms highlights some interesting characteristics of RA-WF 2Q+. In particular, it permits achieving the highest overall system throughput while guaranteeing the requested quality of service for voice applications. Only when the radio resources become scarce with respect to the total offered traffic, RA-WF 2Q+ displays its opportunistic nature, favouring the users nearest to the base station

Section: Scenario With Five Subscriber Stationsmentioning

confidence: 99%

“…§ To have an idea of the behaviour of Mobile WiMAX when different path loss models are employed, the reader can refer to [16]. With respect to WF 2 Q+, the proposed scheduler introduces the number of slots in the downlink frame as a parameter of the sharing decision process.…”

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confidence: 99%

A radio‐aware worst‐case fair weighted fair queuing scheduler for WiMAX networks

Garroppo

Giordano

Iacono

et al. 2012

“…Many papers have been published on the transmission efficiency of IEEE 802.16e systems. Most of these studies evaluate the MAC layer only, that is, deal with scheduling methods, an issue that is not defined in the IEEE 802.16e standard and is left to the base station (BS) and mobile station (MS) vendors’ implementation . Moreover, some papers deal with the performance of transport layer protocols, such as Transmission Control Protocol and User Datagram Protocol, over IEEE 802.16e systems .…”

Section: Introductionmentioning

confidence: 99%

Physical and Medium Access Control criteria for the optimal Medium Access Control protocol data unit size in Automatic Repeat Request‐enabled connections in IEEE 802.16e/ WiMAX systems

Sharon

Alpert

2013

SUMMARYIn this paper, we address an aspect of the mutual influence between the physical (PHY) layer budding blocks (forward error correction (FEC) blocks) and the medium access control (MAC) level allocations in the uplink and downlink of IEEE 802.16e/WiMAX systems. In these systems, it is possible to transmit MAC level frames, denoted MAC protocol data units (PDUs), such that a PDU contains an integral number of fixed size data blocks. We compute the optimal size of a PDU according to two criteria, one related to the PHY layer and one related to the MAC layer. In relation to the PHY layer, the criterion maximizes the average number of data bits that are transmitted in a PHY slot. In relation to the MAC layer, the criterion maximizes the goodput of the PDU. The goodput depends on the success probability of the PDU, which in turn depends on the FEC blocks over which the PDU is allocated. We then compare the maximal PDU goodputs in different sizes of the FEC blocks and the data blocks. The main outcome is that the PDU goodput is sensitive in those cases in which data blocks are very large. We also give guidelines on how to choose the best modulation/coding scheme to use in a scenario where the signal-to-noise ratio can change significantly during transmissions, to maximize the PDU goodput. Finally, we compare between the two criteria. Copyright

“…Cooperative diversity wireless network has a better delay performance compared with noncooperation wireless network.Adaptive modulation and coding (AMC) is used in most of the wireless networks to increase the transmission rate by exploiting the wireless channel variations [8][9][10][11]. The equivalent end-to-end channel model is captured by a finite state Markov channel model representing the multiple states of the Nakagami fading channel, and the delay statistics are obtained by using matrix geometry method.…”

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confidence: 99%

“…Adaptive modulation and coding (AMC) is used in most of the wireless networks to increase the transmission rate by exploiting the wireless channel variations [8][9][10][11]. The problem of applying AMC to a wireless cooperative relay network was investigated in [12].…”

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confidence: 99%

Delay statistics of cooperative automatic repeat request over wireless networks with link adaptation

Huang

Chen

2012

This paper proposes a method to analyze the delay distribution at the transmitter side for cooperative diversity wireless networks with link adaptation, which uses decode-and-forward as a relay strategy. The equivalent end-to-end channel model is captured by a finite state Markov channel model representing the multiple states of the Nakagami fading channel, and the delay statistics are obtained by using matrix geometry method. Cooperative diversity wireless network has a better delay performance compared with noncooperation wireless network.Adaptive modulation and coding (AMC) is used in most of the wireless networks to increase the transmission rate by exploiting the wireless channel variations [8][9][10][11]. The problem of applying AMC to a wireless cooperative relay network was investigated in [12]. In [12], a discrete rate and power adaptation policy was proposed for the fixed-DF relay channel. Transmission during outage was counted as the main cause of error, because capacity achieving codes were assumed, which resolve errors because of channel noise. Although the design of strong and reliable error correction codes has played a key role in error-control for applications with strict delay requirements (e.g., voice), the deployment of delay-tolerant data services in wireless networks makes automatic repeat request (ARQ)-based error-control very attractive to counteract the residual errors without using costly error correction codes at the physical layer.Automatic repeat request protocol is an error-control method of the link layer, which guarantees reliable transferring of packets by retransmitting packets after negative acknowledgments (NACKs) are reported on the feedback channel. There are three basic types of ARQ protocols: stop-and-wait (SW) ARQ, go-back-N (GBN) ARQ, and selective-repeat (SR) ARQ protocols. SR-ARQ is the most efficient one (in terms of throughput); however, GBN-ARQ is superior to the SR-ARQ protocol in terms of implementation simplicity. In [13], an approximate expression of the average delay for SR-ARQ was obtained for a two-state Markov channel under heavy traffic condition. In a multirate wireless network, the delay statistics for SR-ARQ with noninstantaneous feedback delay was derived in [14]. Note that the availability of radio link-level delay statistics allows wireless network design and engineering under statistical delay constraints of the form P r¹delay > D max º < P t instead of those based on the average delay or delay bounds.A finite-state Markov channel (FSMC) model was proposed for Rayleigh and the more general Nakagami-m fading channels in the literature [15][16][17][18][19]. In [15], Zheng et al. presented the crosslayer analytical framework in analyzing the QoS of the DF relaying wireless networks, where AMC is employed at the physical layer under the conditions of unsaturated traffic and finite-length queue at the data link layer. On considering the characteristics of DF relaying protocol at the physical layer, the authors in [15] first proposed modeling a two-hop DF r...