An improved Markov chain description for fading processes

Bergamo, P.; Maniezzo, D.; Giovanardi, A.; Mazzini, G.; Zorzi, Michele

doi:10.1109/icc.2002.997070

Cited by 12 publications

(8 citation statements)

References 8 publications

(19 reference statements)

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“…In order to do so, a wireless station needs the following information a priori: a wireless channel noise model that determines the error performances of the PHY modes, and a conditional probability density function, Ê Ë´Ö ×µ, to model the wireless channel variation. There have been many papers [15][16] [17][18] [19] dealing with the problem of building accurate wireless channel models, which, however, is not the focus of this paper. Our contribution is to propose a simple and effective link adaptation scheme by assuming the availability of such wireless channel models.…”

Section: An Example Of the Best Phy Mode Tablementioning

confidence: 99%

Goodput analysis and link adaptation for IEEE 802.11a wireless LANs

Qiao

Choi

Shin

2002

IEEE Trans. on Mobile Comput.

452

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Abstract-Link adaptation to dynamically select the data transmission rate at a given time has been recognized as an effective way to improve the goodput performance of the IEEE 802.11 wireless local-area networks (WLANs). Recently, with the introduction of the new high-speed 802.11a physical layer (PHY), it is even more important to have a well-designed link adaptation scheme work with the 802.11a PHY such that its fast transmission rates can be exploited. In this paper, we first present a generic method to analyze the goodput performance of an 802.11a system under the Distributed Coordination Function (DCF), and express the expected effective goodput as a closed-form function of the data payload length, the frame retry count, the wireless channel condition, and the selected data transmission rate. Then, based on the theoretical analysis, we propose a novel MPDU (MAC Protocol Data Unit)-based link adaptation scheme for the 802.11a systems. It is a simple table-driven approach, and the basic idea is to pre-establish a best PHY mode table by applying the dynamic programming technique. The best PHY mode table is indexed by the system status triplet that consists of the data payload length, the wireless channel condition, and the frame retry count. At run-time, a wireless station determines the most appropriate PHY mode for the next transmission attempt by a simple table lookup, using the most upto-date system status as the index. Our in-depth simulation shows that the proposed MPDU-based link adaptation scheme outperforms the single-mode schemes and the AutoRate Fallback (ARF) scheme -which is used in Lucent Technologies' WaveLAN-II networking devices -significantly in terms of the average goodput, the frame drop rate, and the average number of transmission attempts per data frame delivery.

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Section: An Example Of the Best Phy Mode Tablementioning

confidence: 99%

Goodput analysis and link adaptation for IEEE 802.11a wireless LANs

Qiao

Choi

Shin

2002

IEEE Trans. on Mobile Comput.

452

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“…In 2002 Bergamo et al [8] proposed a multidimensional FSCM model where the state-space consisted of amplitude and rate-of-change of the fading envelope. The rate-of-change space was divided in three states that represented the rate being either negative, positive or zero.…”

Section: Finite-state Markov Channelsmentioning

confidence: 99%

A computationally efficient simulation chain for OFDM-based wireless systems

Poikonen

Ojaniemi

Nybom

et al. 2011

2011 IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB)

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We present a method for modeling OFDM transmission over time-and frequency-selective fading channels using finite-state hidden Markov models. The proposed approach has improved fading autocorrelation accuracy compared to previous related models. Also, we present a way of producing log likelihood ratio values as output of the finite-state model for any signal constellation. As a case study, we configure the proposed model according to the second generation terrestrial digital video broadcast system operating over a typical urban mobile channel.

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“…The transmitter can estimate the transmitter-receiver distance d by observing the several packets of signal strengths -there are several methods to making accurate estimations (e.g. [4], [10], [11]), which, however, is out of scope of this paper. Fig 4 shows …”

Section: Description Of Ilarimentioning

confidence: 99%

An Enhanced Link Adaptation Strategy for IEEE 802.11 Wireless Ad Hoc Networks

Yang¹,

Choi²,

Kim³

et al. 2007

2007 International Conference on Wireless Communications, Networking and Mobile Computing

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The multi-rate capability provided by the IEEE 802.11 physical layer requires that the MAC layer adapts the transmission rate according to the receiver-side channel conditions. Many link adaptation schemes for a multi-hop wireless ad hoc network have been proposed so far where most of them probe the receiver's channel condition using RTS/CTS handshake and select the highest attainable data rate at which the receiver can decode successfully. A key problem with such schemes is that they do not consider the interference from hidden nodes in multi-hop and multi-rate environments, and hence, they may not work properly since the higher rate also increases the probability of interference. In this paper, we investigate the relation between interference and transmission rates and show that a transmitter can achieve higher performance by transmitting at the decreased rate in multi-hop ad hoc networks. Based on the observation, we present a new effective link adaptation scheme that integrates the receiver-based and senderbased techniques and determines the best transmission strategy taking the interference as well as the receiver's channel quality into consideration.

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An improved Markov chain description for fading processes

Cited by 12 publications

References 8 publications

Goodput analysis and link adaptation for IEEE 802.11a wireless LANs

Goodput analysis and link adaptation for IEEE 802.11a wireless LANs

A computationally efficient simulation chain for OFDM-based wireless systems

An Enhanced Link Adaptation Strategy for IEEE 802.11 Wireless Ad Hoc Networks

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