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The Quality of Service (QoS) on the traffic environment with high mobility, dynamic topology, and change trajectory is one of the challenges in the use of Vehicular Ad-Hoc Networks (VANET) Routing Protocols. PUMA routing protocol presents multicast work mechanism based on shared mesh topology. It always dynamically adapt to VANET traffic conditions. In this paper, we evaluated the PUMA routing protocol...
In this paper, we develop a queueing analysis for opportunistic decode-and-forward (DF) relay networks. It is assumed that the networks undergo Nakagami-m fading and that the external arrival process follows a Poisson distribution. By selecting the best relay according to the opportunistic relaying scheme, the source first transmits its signal to the best relay which then attempts to decode the reception...
Adaptive modulation and coding (AMC) and opportunistic scheduling are widely used in modern broadband wireless communication systems to adapt to time-dependent user-dependent channel fading. On one hand, AMC and opportunistic scheduling can adapt to channel variations and take advantage of multiuser diversity to effectively improve throughput. On the other hand, due to the user-dependent wireless...
In this work, we propose an instantaneous rate based cooperative medium access control (MAC) protocol (termed as IrcMAC) and compare its performance gain over the existing cooperative MAC protocols under heavy load and fast fading conditions. CoopMAC I protocol, proposed in [5] which selects either direct path or relay path based on rate comparison to enhance average throughput and delay, performs...
This paper presents a low-power MMSE MIMO detector using a dynamic voltage wordlength scaling (DVWS) technique for 4×4 MIMO-OFDM systems. A MIMO MMSE detector requests high performance computing for real-time processing. A pipelined MMSE detector using Strassen's algorithm has been developed in our previous work. However, it consumes significant power and thus, we have to consider a low-power solution...
We consider in this paper downlink scheduling at the Medium Access Layer (MAC) layer for delay sensitive traffic in wireless systems based on Orthogonal Frequency Division Multiple Access (OFDMA). We refer in particular to next generation wireless systems such as 3GPP-LTE. We propose an Opportunistic Packet Loss Fair (OPLF) scheduling algorithm based on calculating a simple dynamic priority function...
To better exploit the spectrum resources a wireless sensor network can be used to assists a secondary cognitive radio network by providing information about the current primary spectrum occupancy. In this paper we study the performance of the secondary network when it is co-located with and having similar cell size as a mobile primary network that uses a cellular reuse pattern with seven frequencies...
Cooperative diversity employs relays to assist source-destination transmissions and has shown to improve link outage probability in multipath fading environments. In this paper, we model relay selection as a semi-Markov process to analyze the impact of relay selection overhead on throughput, delay, and jitter in a simple scenario. Results show that the selection overhead can significantly reduce benefits...
Different alternatives for uplink transmit diversity for HSUPA are being investigated in 3GPP. This paper compares the performance of two-antenna beamforming using closed loop feedback information against the baseline single antenna transmission. With beamforming, multiple transmit antennas are utilized and the UE transmitter applies a weight vector to the transmit antennas in order to amplify the...
A Sensor Network Aided Cognitive Radio Network uses the concept of a wireless sensor network that assists a cognitive radio network by providing information about the current primary spectrum occupancy. In this paper we study the performance of the cognitive network for various cell sizes and transmit power levels when deployed co-located with a mobile primary system that uses a cellular reuse pattern...
We study a problem of optimal resource allocation in cooperative communication network with finite state fading channels and queueing. The control problem is to assign resources dynamically within the cloud of mobile users subject to the longterm average power constraint in order to stabilize the queues and maximize the long-term average throughput of the system. By modeling the problem as a finite...
The maximum traffic arrival rate at the network for a given delay guarantee (delay constrained throughput) has been well studied for wired channels. However, few results are available for wireless channels, especially when multiple antennas are employed at the transmitter and receiver. In this work, we analyze the network delay constrained throughput of a multiple input multiple output (MIMO) wireless...
In the paper, we consider the end-to-end routing and link scheduling problem for multi-hop wireless sensor networks. The efficient link scheduler under our consideration is intended to assign time slots to different users so as to minimize channel usage subject to constraints on data rate, delay bound, and delay bound violation probability. We also present a coupled robust multi-path routing structure...
We consider the impacts of channel fading on the quality of service (QoS) performance of the IEEE 802.11 system. Traditional 2-D Markov chain models, while suitable for throughput analysis, are unable to capture the QoS performance due to the lack of a proper queueing model. We present a 3-D Markov chain queueing model that incorporates channel fading effects and solve the Markov chain efficiently...
With the extensive deployment of 802.11 wireless local area networks (WLANs) and the need for better quality of service (QoS), the 802.11e MAC with service differentiation was developed. Analysing the effect of fading, shadowing and near-far effect on the performance of 802.11 is a fundamental consideration in practical situations since the wireless channels are errorprone.This paper develops a p-persistent...
This paper investigates the downlink system level performance for Layer-3 (L3) and Layer-1 (L1) relays with orthogonal frequency division multiple access (OFDMA) used in LTE-Advanced. Various practical factors are taken into account in the evaluations such as the processing delay and upper-bound of the amplifier gain of the L1 relay, capacity limitation of the backhaul channels, and empty buffer status...
This paper proposes a novel admission control (AC) algorithm for guaranteed quality of service (QoS) to all users. The proposed solution provides better utilization of system capacity using adaptive modulation (AM). A scheduler based on a per user priority function is also given in this paper. The AC is given by allocating the exact number of slots for each user that will meet its QoS. For every new...
For efficient sensor coverage of large industrial and incident areas, fast and flexible strategies for collecting optical sensor data through an autonomous, wirelessly connected swarm of Micro Unmanned Aerial Vehicles (MUAV) is still an emerging challenge. Of particular interest are strategies for spatial coverage optimization of mobile networks and the acquisition of high quality image material targeting...
The performance of multi-hop multiple-input, multiple-output (MIMO) communication scenarios is evaluated for space time block coded (STBC) and the proposed distributed cyclic delay diversity (CDD) technique. By increasing the frequency selectivity, multi-stage CDD with low complexity implementation yields significant performance improvement as relaying network. Both diversity techniques based on frequency-correlated...
Wireless ad hoc networks are an emerging and popular technology to the world; however, the benefits of them are actually their fragility, too. Owing to mobile node movement, the link break problem always occurs in the network. The problem greatly influences the throughput, delay, jitter, and lots of performance issues of a routing protocol. Hence, this article is proposed to evaluate the influence...
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