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A stochastic model is presented in this paper for packet-level performance analysis of the medium access control (MAC) schemes considered for adoption in smart utility networks. Smart grid communications involve critical issues in terms of reliability and timeliness, and the MAC largely determines efficiency of packet-level communication within the immediate neighborhood. Powerline communication (PLC),...
The IEEE 802.11 standardization group has recently ratified 802.11ac as the newest major amendment of the 802.11 family of Wi-Fi standards. While 802.11ac has specified a number of improvements over 802.11n such as: (i) 8 spatial streams (ii) mandatory bandwidth of 80 MHz and (iii) multi-user MIMO on the downlink, these improvements mostly target to improve the per-link throughput, and in case of...
Like physical systems can exist in different phases, the concept of different phases (or states) can be also attributed to other types of systems, such as wireless networks. In this paper we employ the notion of phase diagrams to characterize a wireless network by means of a reduced number of simulation points. By reducing the amount of simulations - compared to fine-grained simulation-based analyses...
This study examines the trade-offs related to the problem of coverage auto-configuration of open access small cells (SC) that (i) are on-demand deployed in the macro-cells (MC) of a W-CDMA network, and (ii) operate in the same frequency channel as the hosting/neighboring MCs. The goal is to identify stable and practically detectable equilibrium states whose achievement can represent an optimality...
In this paper, we investigate a super dense cellular deployment case in which the cells are continuously added in order to increase the total network capacity. The effect of the other cell interference in the HSPA network is analyzed, which provides an insight into the aggregated interference impact on the cell capacity. The network capacity performance with varying cell densities has been studied...
In a vehicular ad hoc network (VANET), basic safety messages (BSM) are exchanged among vehicles to provide cooperative awareness and support safety applications. While the periodic generation and transmission of such messages already place a heavy burden on the network load, the hidden nodes further complicate the network situation with packet collisions being undetectable. In this paper, we propose...
The traditional vertical handover schemes postulate that vertical handover of each user comes on an individual basis. This enables the users to know previously the decision already made by other users, and then the choice will be made accordingly. However, in the case of a group vertical handover, almost all the VHO decisions — which will certainly choose the best network, will be made at the same...
In the past few years, an exciting progress has been made on CSMA (Carrier Sense Multiple Access) algorithms that achieve throughput and utility optimality for wireless networks. However, most of these algorithms are known to exhibit poor delay performance making them impractical for implementation. Recently, several papers have addressed the delay issue of CSMA and yet, most of them are limited,...
Carrier Sense Multiple Access (CSMA) protocols have been shown to reach the full capacity region for data communication in wireless networks, with polynomial complexity. However, current literature achieves the throughput optimality with an exponential delay scaling with the network size, even in a simplified scenario for transmission jobs with uniform sizes. Although CSMA protocols with order-optimal...
LP relaxations of Maximum Weighted Independent Set (MWIS) problems have been widely studied. A key motivation for this prior work comes from the central role that MWIS plays in designing throughput-optimal algorithms for wireless networks. However, to the best of our knowledge, the actual packet delay performance of these algorithms has not been studied in the context of wireless networks. In this...
Recently, several CSMA algorithms based on the Glauber dynamics model have been proposed for multihop wireless scheduling, as viable solutions to achieve the throughput optimality, yet simple to implement. However, their delay performance still remains unsatisfactory, mainly due to the nature of the underlying Markov chains that imposes a fundamental constraint on how the link state can evolve over...
Full-duplex has emerged as a new communication paradigm and is anticipated to double wireless capacity. Existing studies of full-duplex mainly focused on its PHY layer design, which enables bidirectional transmission between a single pair of nodes. In this paper, we establish an analytical framework to quantify the network-level capacity gain of full-duplex over half-duplex. Our analysis reveals that...
Carrier Sense Multiple Access with Enhanced Collision Avoidance (CSMA/ECA) is a distributed MAC protocol for WLANs, capable of achieving greater throughput than the current contention mechanism in WLANs. It does so by changing to a deterministic backoff after successful transmissions, which leads to a collision-free schedule that under ideal conditions can be permanently maintained. This demo shows...
Game-theoretic modeling and equilibrium analysis have provided valuable insights into the design of robust local control rules for the individual agents in multi-agent systems, e.g., Internet congestion control, road transportation networks, etc. In this paper, we introduce a non-cooperative MAC (Medium Access Control) game for wireless networks and propose new fully-distributed CSMA (Carrier Sense...
Co-channel interference exists in IEEE 802.11 based wireless local area networks (WLANs) due to the limited number of non-overlapping channels in the current standards. In this paper, we investigate the impact of co-channel interference in carrier sense multiple access with collision avoidance (CSMA/CA) based WLANs via simulation. We find that the throughput unfairness among the users is severe in...
It is emerging to deploy multihop cellular networks (MCNs) for increasing cell capacity and to provide large coverage to mobile users without increasing infrastructure cost. It very much decreases the dead-spot and hot-spot problems with rapidly growing mobile users in cellular networks. However, channel assignment is the most important concern in these networks. Quite a few recent proposals has been...
In IEEE802.11 standard, a method based on RTS and CTS is adopted as the method to solve the hidden terminal problem in ad-hoc networks. However, the throughput by this method greatly degrades when the traffic volume increases, because of the occurrence of collisions between RTSs or between CTS and DATA. Thus, we propose in this paper, we propose a method to improve the throughput of ad-hoc networks,...
Wireless full-duplexing enables multi-hop wireless networks to increase network performance, such as the end-to-end throughput. However, the combination of wireless full-duplexing and multi-hop communication produces a secondary transmission collision problem due to the increase of transmission opportunities. This paper proposes directional asynchronous full-duplex medium access control (DAFD-MAC)...
Inspired by the discrepancy between past theoretical analysis and real measurements for high-load scenarios for inter-session network coding, we pinpoint and analyze the source of this discrepancy in wireless networks implementing a CSMA/CA medium access scheme. Our analysis shows that CSMA/CA is very sensitive to asymmetric channel losses caused by channel conditions. Leveraging this analysis, we...
This paper presents an adaptive access scheme for Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) aiming to take advantage of multi-user diversity and improve throughput, while supporting distributed and asynchronous operation. By assigning channel-adaptive access probabilities to different users, this method prioritizes users who gain most from using a channel, and hence, improves...
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