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In this paper we propose a novel deblocking filter architecture using register array structure for standard video codec hardware. The proposed register array consists of multiple sub-macroblocks for a single macroblock and several sub-macroblock registers for the up and left neighboring macroblocks. The operation procedure of the register array is also presented. The proposed register array achieves fast operating speed and small circuit size at the same time.

Due to the open and dynamics nature of ubiquitous computing environments and services, quantitative service differentiation is needed to provide controllable quality of service (QoS) levels to meet changing system configuration and resource availability and to satisfy different requirements of applications and users. A proportional differentiation model was proposed in the DiffServ context, which states that QoS factors of certain classes of aggregated traffic be proportional to their differentiation weights. While it provides compelling proportionality fairness to clients, it lacks of the support of a server-side QoS optimization with respect to the resource allocation. In this paper, we propose and promote a square-root proportional differentiation model for delay-sensitive Internet services. Interestingly, both popular QoS factors with respect to delay, queueing delay and slowdown, are reciprocally proportional to the allocated resource usages. We formulate the problem of quantitative service differentiation as a resource allocation optimization towards the minimization of , defined as the sum of weighted responsiveness of client request classes. We prove that the optimization-based resource allocation scheme essentially provides square-root proportional service differentiation to clients. We then propose a generalized rate-based resource allocation approach. Simulation results demonstrate that the approach provides quantitative service differentiation at a minimum cost of system delay.

This work presents a power-efficient route discovery protocol (PERDP) to reduce signaling overhead of the power-efficient routing (PER) mechanism for Opportunity Driven Multiple Access (ODMA) networks. An analytical method was proposed to derive the control parameters to achieve a given connectivity probability. Simulation results demonstrate the accuracy of the analysis and the superiority of the proposed PERDP. It is found that the signaling overhead of the proposed PERDP is 12.03% and 24.85% lower than that of dynamic source routing (DSR) and PER mechanism, respectively, under 90% connectivity probability in a high UE-density environment.

Agricultural monitoring using wireless sensor networks has gained much popularity recently. In this paper, we review five existing flat-tree routing algorithms and proposed a new algorithm suitable for applications such as paddy field monitoring using wireless sensor network. One of the popular data collection methods is the data aggregation approach, where sensor readings of several nodes are gathered and combined into a single packet at intermediate relay nodes. This approach decreases the number of packets flowing and minimizes the overall energy consumption of the sensor network. However, most studies in the past do not consider the network delay in this context, which is an essential performance measure in real-time interactive agricultural monitoring through Internet and cellular network. We propose an algorithm called Information Selection Branch Grow Algorithm (ISBG), which aims to optimize the network in achieving higher network lifetime and shortening the end-to-end network delay. The performance of this algorithm is assessed by computer simulation and is compared with the existing algorithms used for data aggregation routing in wireless sensor networks.

This paper presents a Dynamic Reconfiguration of Mobile IP Agents (DRMIPA) and failure free architecture integrated in Mobile Ad hoc Networks (MANETs). The proposal is due to the fact that: actual infra-structured networks do not implement the Mobile IP (MIP) protocol, all MIP agents are static and the cost of having redundancy for MIP agents’ failure is often high. As MANETs are created temporarily at any location, we propose a solution that would allow the integration of MIP with MANET. Doing so, groups of MIP nodes in MANETs would enjoy the IP mobility at any foreign or local network that doesn’t implement MIP. New algorithms and messages are proposed for the new Dynamic Reconfiguration and fault tolerant Mobile IP Agents in MANET. A simulation performance analysis using the Network Simulator (NS2) is presented.

An operation is called if a node sends a packet to all other nodes in an ad hoc network. Broadcasting is an elementary operation to support many applications in ad hoc networks. Thus, many schemes have been proposed for reducing the number of re-broadcasting packets. However, to the best of our knowledge, few papers discuss the bound of necessary broadcasting packets. In the work, we derive formulas for estimating the number of required broadcasting packets by taking three different approaches. In addition, we also propose two protocols: the cluster-head-early method and the connected- dominating-set method to reduce the redundant rebroadcast packets without exploiting the mechanisms of hello messages or cluster formation.

This paper proposes an analytical model of IEEE 802.15.4, which is a standard toward low complexity, low power consumption and low data rate wireless data connectivity. In this paper, we concentrate on the MAC performance of the IEEE 802.15.4 LR-WPAN in a star topology with unslotted CSMA/CA channel access mechanism under non-saturated modes. Our approach is to model stochastic behavior of one device as a discrete time Markov chain model. We believe that many WSN applications would benefit from our analytical model because many applications in WSN generate traffic in non-saturated mode. We obtain five performance measures : throughput, packet delay, number of backoff, energy consumption and packet loss probability. Our results are used to find optimal number of devices satisfying some QoS requirements.

Well-scheduled communications, in conjunction with the aggregation of data reduce the energy waste on idle listening and redundant transmissions. In addition, the adjustable radii and the number of retransmissions are considered to reduce the energy consumption. Thus, to see that the total energy consumption is minimized, we propose a mathematical model that constructs a data aggregation tree and schedules the activities of all sensors under adjustable radii and collision avoidance conditions. As the data aggregation tree has been proven to be a NP-complete problem, we adopt a LR method to determine a near-optimal solution and furthermore verify whether the proposed LR-based algorithm, LRA, achieves energy efficiency and ensures the latency within a reasonable range. The experiments show the proposed algorithm outperforms other general routing algorithms, such as SPT, CNS, and GIT algorithms. It improves energy conservation, which it does up to 9.1% over GIT. More specifically, it also improves energy conservation up to 65% over scheduling algorithms, such as S-MAC and T-MAC.

When using shortest-distance routing for mobile ad-hoc networks (MANETs), the physical distances of links that constitute such paths tend to be very long since this leads to fewer hops between source and destination nodes. However, if the physical distance of a wireless link becomes so long that it approaches its transmission range, packet transmission error rates can increase drastically, resulting in an unstable link. Furthermore, packets are more likely to be lost due to external environment factors such as white noise and wireless interference if the signal strength is not strong enough. Therefore, it would be desirable for routing algorithms for MANETs to be able to select paths that are more likely to be stable. With this objective in mind, we propose an enhanced stability model (ESM) to estimate link stability based on signal strength. A routing algorithm based on this new model is also proposed. Simulations of the proposed ESM and previous link estimation models validate the superiority of the proposed approach. Simulations also show that the proposed routing algorithm performs particularly well when there are unreliable links.

This paper proposes a new phase estimation algorithm for turbo-coded OFDM systems at low SNR. In the proposed algorithm, phase estimation process is implemented jointly with iterative decoding process. This algorithm uses extrinsic information at each decoding iteration to estimate OFDM carrier phase rotations instead of using pilots. The proposed algorithm iteratively estimates phase rotation at each OFDM carrier by averaging soft decision extrinsic information carrier by carrier. The algorithm significantly reduces pilot insertion and thus, it is suitable for low operating SNR systems. Simulation results show that the proposed algorithm achieves significantly improved phase estimation compared to the conventional pilot assisted phase estimation and it converges to perfect phase estimation case.