Stability of slotted ALOHA with spatial diversity

Naware, V.; Tong, Lang

doi:10.1109/icc.2003.1204220

Cited by 3 publications

(5 citation statements)

References 21 publications

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“…The MPR matrix, in general, depends on the channel characteristics, the type of modulation used, and the multiuser detection/equalization method receivers apply. A variety of physical layers have been modeled using MPR and its variants (e.g., CDMA [20]- [22] and multiple antenna uplink [23], [24] A motivation for considering the -collision channel comes from the CDMA with matched filter. In the common SINR (signal-to-interference-plus-noise ratio) threshold model for CDMA [25], a transmitter is considered successful if its power divided by the noise plus interference exceeds a certain threshold.…”

Section: Network Modelmentioning

confidence: 99%

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Stability and Capacity of Regular Wireless Networks

Mergen

Tong

2005

IEEE Trans. Inform. Theory

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Abstract-We study the stability and capacity problems in regular wireless networks. In the first part of the paper, we provide a general approach to characterizing the capacity region of arbitrary networks, find an outer bound to the capacity region in terms of the transport capacity, and discuss connections between the capacity formulation and the stability of node buffers. In the second part of the paper, we obtain closed-form expressions for the capacity of Manhattan (two-dimensional grid) and ring networks (circular array of nodes). We also find the optimal (i.e., capacity-achieving) medium access and routing policies. Our objective in analyzing regular networks is to provide insights and design guidelines for general networks. The knowledge of the exact capacity enables us to quantify the loss incurred by suboptimal protocols such as slotted ALOHA medium access and random-walk-based routing. Optimal connectivity and the effects of link fading on network capacity are also investigated.

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Section: Network Modelmentioning

confidence: 99%

“…By substituting specific , the MPR model and several other models can be obtained as special cases [23], [24], [30], [39], [40].…”

Section: A Extensions To a General Network Model With Asymmetric Andmentioning

confidence: 99%

Stability and Capacity of Regular Wireless Networks

Mergen

Tong

2005

IEEE Trans. Inform. Theory

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“…The latter condition amounts to requiring some form of capture, and is typically not satisfied when the number of contending users exceeds the capability of the multiuser detector (in which case, most likely, all users fail to decode). There are also other similarly restrictive stability conditions that have been considered in the literature, such as assuming a lower bound on the signal-tointerference ratio [69]. In a wireless network with mobiles contending for communicating with an AP, however, the AP can control the contention policies used by the mobiles based on its knowledge of the network conditions.…”

Section: Motivationmentioning

confidence: 99%

“…However, the potential delay from waiting for an idle channel [54] makes support of real-time traffic difficult. Another technique is capture [22], [37], [40], [58], [69], [79], [117], in which a stronger transmission may be successful even if there are some weaker simultaneous transmissions. The effect of capture in an ALOHA system can be enhanced by employing spread-spectrum techniques [8], [9], [22], [77], [83], in which users employ symbol spreading, or space-division multiple access (SDMA) [106], [116], wherein multiple antennas are used to isolate multiple received transmissions.…”

Section: Introductionmentioning

confidence: 99%

Multiuser Detection

Basics of Code Division Multiple Access (CDMA)

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This dissertation represents a major milestone in my life and it has been reached, and the next steps will be taken with the support and friendship of some people very special to me. I would like especially to thank my parents whose love, advice, and encouragement have always inspired me to take the next steps; my brother, Erik, whose art and creativity have been an inspiration; Iva, who has been an unmatched source of love, laughter and friendship; my Grandma, who, even though she missed the grade where you learn fractions, was the first person published in my family; Pat DuBois for her tireless support; Miki and Manjo for their warmth; and Rally, who has always kept me company and chased away the stress. I would like to thank my advisor, Professor Madhow, for his vision, guidance, support and limitless patience. Thank you to my committee members, Professors Belding-Royer, Cruz, Gibson, Rose, and Shynk for their discussion and comments in bringing this project to fruition. And navigating all the channels at UCSB would have been impossible without Valerie De Veyra. I received continued motivation also from the students who were in my T.A. sections over the years. There have been a few key individuals along the way who helped even to reach this point, and I am thankful to Ms. Koslove, Mrs. Michaels, and Prof. G. Finally, this has been an education in life for me, and I am thankful for the people who have enriched all its aspects: Raghu for his unlimited capacity for debate on any topic; Noah for the calls to get to the gym; Suk-seung for the study hours; Kris C. and John K. for keeping a great environment; Nick Angelov for laughing (at me); Steve T. for his energy; John B. for that mid-western connection. I would like to thank a great friend and light in the darkness, Jelena. A host of others who all make my experience here special:

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“…The latter condition amounts to requiring some form of capture, and is typically not satisfied when the number of contending users exceeds the capability of the multiuser detector (in which case, most likely, all users fail to decode). There are also other similarly restrictive stability conditions that have been considered in the literature, such as assuming a lower bound on the signalto-interference ratio [7]. In a wireless network with mobiles contending for communicating with an access point (AP), however, the AP can control the contention policies used by the mobiles based on its knowledge of the network conditions.…”

Section: Introductionmentioning

confidence: 99%

A QoS framework for stabilized collision channels with multiuser detection

Bruvold

Mudumbai

Madhow

IEEE International Conference on Communications, 2005. ICC 2005. 2005

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Recent work has shown that cross-layer optimization of the physical layer and Medium Access Control for a wireless collision channel, based on a receiver with adaptive multiuser detection capability, is capable of providing significantly better performance than classical Aloha. The basic features of such a system are multipacket reception (MPR) capability, and the ability (with high probability) to estimate the number of contending users even when the packets are not successfully received. We provide an analytical model that includes these features, and use it to derive methods for backlog estimation and stabilization. Two classes of users are considered: high priority users with Quality of Service (QoS) requirements, who must succeed within a deadline with a specified probability; and low priority users whose throughput we wish to maximize, while maintaining the QoS for high priority users, and keeping the overall system stable. We obtain contention policies that ensure QoS and stability, based on backlog estimates obtained by extending Rivest's pseudo-Bayesian technique for classical Aloha. The channel throughput and the achievable QoS is characterized as a function of the arrival rates for high and low priority users. Finally, we apply these methods to simulations of a system employing Differential Minimum Mean Squared Error (DMMSE) adaptive multiuser detection, and find that the analytical model provides accurate guidelines for design and performance predictions.

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Stability of slotted ALOHA with spatial diversity

Cited by 3 publications

References 21 publications

Stability and Capacity of Regular Wireless Networks

Stability and Capacity of Regular Wireless Networks

Multiuser Detection

A QoS framework for stabilized collision channels with multiuser detection

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