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In the last years, there has been an increasing interest in developing and testing Medium Access Control (MAC) protocols for ad hoc networks based on optimal methods. Several solutions do not take into account the throughput-fairness tradeoff, presenting high throughput performance but under-performing in terms of medium access fairness. This work presents a novel MAC scheme, which is designed to...
In the last years, there has been an increasing interest in developing and testing Medium Access Control (MAC) protocols for ad hoc networks based on optimal methods. The solutions already proposed in several works are generally hard to implement because they require extensive message passing among the nodes. Moreover, a relaxation for the optimal solution is generally needed to achieve an implementable...
This paper considers the use of SC modulations (Single-Carrier) with FDE (Frequency-Domain Equalization) with low-complexity soft combining ARQ schemes (Automatic Repeat reQuest). With our technique, packets associated to different transmission attempts are combined in a soft way, allowing improved performances. Its low complexity makes it particularly interesting for the uplink of wireless systems...
The design of efficient medium access control (MAC) protocols that are backward compatible to legacy IEEE 802.11-based protocols is a central issue in the literature. This paper draws inspiration from utility-driven max-weight policies that lead to the maximum throughput region in synchronized slotted systems. It introduces two important enhancements to the IEEE 802.11 MAC protocols, which are not...
This paper introduces two important enhancements to the IEEE 802.11 medium access control (MAC) protocols which are not considered in the current IEEE 802.11 MAC protocol: the channel state between the transmitter and the receiver and the node queue state. Our objective is to characterize the impact of these parameters on medium access regulation, and ultimately rely on them in order to enhance the...
This paper deals with multi-packet detection for SC modulations (Single-Carrier) with FDE (Frequency-Domain Equalization). We consider iterative frequency- domain receivers that jointly perform the equalization, multi-packet separation and channel decoding operations. Our receivers allow a high throughput provided that the number of mobile terminals that is trying to access a given slot is equal to...
This work presents a simple method to estimate IEEE 802.11 distributed coordination function (DCF) service time. This is the total amount of time needed to transmit a given frame, which is defined as the duration from the instant a node starts the transmission, until the instant when the transmission task effectively finishes. We are motivated by the fact that IEEE 802.11 DCF does not provide time-bounded...
In a beaconing scheme (BS) each network node periodically broadcasts messages (beacons) to obtain and maintain an image of the network physical topology. Nodepsilas mobility and issues related with the communication process could degrade the BS view accuracy. This work proposes a novel method to improve the BS robustness face to the communication process drawbacks. Assuming a homogeneous traffic load,...
This paper proposes MH-MAC, a new MAC protocol for wireless sensor networks capable of handling applications that generate infrequent huge peaks of traffic. Existing protocols are not adapted to this kind of applications. Asynchronous protocols are energy efficient for the long inactive periods, but fail to cope with the bandwidth and latency requirements of the traffic peaks when more than two nodes...
The strong research on the performance of the IEEE 802.11 standard seen lately contributes to a better understanding of the network and as a starting point for the design of future networks (specially in the ad-hoc area). Oliveira et al. proposed a model to study the IEEE 802.11 DCF delay assuming saturated or non-saturated broadcast and unicast traffic. Oliveira et al. assumes that all nodes generate...
The existing models for IEEE 802.11 DCF networks only consider unicast frames, ignoring the existence of broadcast traffic. In a real scenario, the stations are most of the times non-saturated and unicast and broadcast frames exist. These specific characteristics influence the service time which consequently affects the queue behaviour. In this paper, the authors model the total frame's delay for...
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