Packet Arrival Rate Research Articles

A GTS Allocation Scheme to Improve Multiple-Access Performance in Vehicular Sensor Networks

The IEEE 802.15.4 protocol is designed to flexibly support both real-time and contention-based services. When the beacon model is enabled, guaranteed time slot (GTS) scheduling can provide contention-free access to latency-sensitive services based on the time-division multiple-access mechanism. This characteristic makes IEEE 802.15.4 the appropriate candidate for vehicular sensor networks in which mobile nodes need to exchange packets with roadside units (RSUs) within a limited duration. In this paper, using network calculus theory, we analyzed the relationship between time-slot utilization and the corresponding access parameters, such as packet arrival rate, burst size, and vehicles' mobility extent. Then, for a given number of vehicles preparing to access an RSU, we proposed a time-sensitive weighted round-robin (TS-WRR) scheduler to improve the multiple-access performance, which can take the service delay requirement, packet arrival rate, and vehicular mobility level into account. Next, the weight determination and time-slot allocation strategy of the TS-WRR scheduler were issued in detail, which incorporate the special limitations and application requirements in a vehicle-to-infrastructure (V2I) communication environment. To make our model feasible for testing, we also elaborately demonstrated the implementation procedure with pseudocode and simulator design. Numerical results show that our TS-WRR scheduler outperforms some classic schedulers such as First-Come First-Served and WRR, as well as two latest works, i.e., implicit GTS allocation scheme and adaptive real-time GTS allocation mechanism in terms of delay guarantee and GTS utilization maximization in vehicular sensor networks.

PERFORMANCE ANALYSIS OF CSMA WITH MULTI-PACKET RECEPTION: THE INHOMOGENEOUS CASE

The problem of carrier sense multiple access (CSMA) with multi-packet reception (MPR) is studied. Most prior work has focused on the homogeneous case, where all the mobile users are assumed to have identical packet arrival rates and transmission probabilities. The inhomogeneous case remains largely open in the literature. In this paper, we make a first step toward this open problem by deriving throughput and delay expressions for inhomogeneous CSMA, with a particular focus on a family of MPR models. This family of MPR models, which allows us to overcome several challenges associated with conventional analysis, is general enough to include a number of interesting MPR techniques—such as successive interference cancellation, compute-and-forward (CF we also evaluate the performances of various MPR techniques, highlighting the clear advantages offered by SCF.

Energy analysis for the distributed receiver‐based cooperative medium access control for wireless sensor networks

This paper presents the energy analysis of a new energy-efficient distributed receiver-based cooperative medium access control (MAC) scheme for wireless sensor networks. The cooperative MAC scheme developed herein incorporates cooperation, overhearing avoidance, receiver-based relay node selection and a Markov-based channel state estimation onto the standard IEEE 802.15.4 scheme. The solution is developed based on a receiver oriented approach when selecting cooperative relay nodes and using a store and forward scheme to relay the packets to the destination node. This works’ main focus is in combining the cooperative packet relaying with overhearing avoidance in order to reduce node energy consumption hence enhancing the network lifetime. As the performance criteria, the energy consumed per node is investigated against packet arrival rate and average signal-to-noise ratio. The percentage of energy consumed and packet throughput are also investigated as the proposed MAC scheme is compared against the standard IEEE 802.15.4 MAC over the estimated channel conditions. The results show that the proposed MAC scheme with cooperation and overhearing avoidance resulted in both improved performance and improved energy saving patterns.

Network Layer Scheduling and Relaying in Cooperative Spectrum Sharing Networks

We consider network layer cooperation in spectrum sharing networks whereby some secondary users relay primary users' packets, in return for more favorable spectrum access rules. Under this cooperative scheme, we investigate how primary and secondary networks can be stabilized without explicit knowledge of the packet arrival rates. We consider a primary packet generation process wherein a packet is formed by aggregating constant amount of bits that arrive in every time slot from upper-layers of the primary transmitter. For this primary packet generation model we develop a relaying and scheduling algorithm using Lyapunov drift techniques that does not require knowledge of packet arrival rates. We also construct a guaranteed stability region representing packet generation rates for which the algorithm can stabilize the network. The set of secondary packet generation rate vectors for which the network can be stabilized do not decrease under cooperation when the primary packet generation rate is lower than what can be maximally supported without cooperation. For higher primary packet generation rates the algorithm stabilizes the network for a non-empty set of secondary packet generation rate vectors.

A dynamic allocation mechanism of delivering capacity in coupled networks

Traffic process is ubiquitous in many critical infrastructures. In this paper, we introduce a mechanism to dynamically allocate the delivering capacity into the data-packet traffic model on the coupled Internet autonomous-system-level network of South Korea and Japan, and focus on its effect on the transport efficiency. In this mechanism, the total delivering capacity is constant and the lowest-load node will give one unit delivering capacity to the highest-load node at each time step. It is found that the delivering capacity of busy nodes and non-busy nodes can be well balanced and the effective betweenness of busy nodes with interconnections is significantly reduced. Consequently, the transport efficiency such as average traveling time and packet arrival rate is remarkably improved. Our work may shed some light on the traffic dynamics in coupled networks.

Performance Analysis of the IEEE 802.16 Uplink for Best-Effort Traffic

The IEEE 802.16 has a reservation based, centralized approach for allocating bandwidth on the upstream channel. In this paper, we proposed a queue length based weighted round robin (QL-WRR) scheduling algorithm to assess the efficient usage of upstream bandwidth of the IEEE 802.16 MAC protocol. This scheduling algorithm provides fairness. In QL-WRR scheduling algorithm, the scheduler takes the arrival rates of packets at the SS's into account. A mathematical model is developed to determine the probability transmission by an SS, and probability of collision in a minislot. These parameters are used to obtain the uplink performance. The proposed mathematical model allows the dynamic variation of ratio between contention and data minislots according to the network load to improve the uplink utilization.

Distributed Queue-Aware Relay Node Selection for Cooperative Wireless Networks via Vickrey Auction Game

Queue-aware relay selection for the uplink of a user cooperation multiple access wireless network is investigated. To achieve better overall quality-of-service (QoS), the queue states of the relay buffers are considered in the relay selection process. A distributed relay selection mechanism based on a Vickrey auction game is proposed. It is shown that with a strictly positive reserve price, the unique Nash equilibrium of the auction game achieved by a truthful bidding strategy is the best relay response under the queue length constraint. Numerical results show that a significant improvement in QoS provisioning is achieved using the proposed auction-based queue-aware relay selection, compared to fixed relaying and channel-aware relay selection, especially when the relays have high average packet arrival rates. Given a target system packet blocking rate, the proposed scheme helps to better maintain relay buffer queue stability.

Distributed Cross-layer Power Control in Pre-equalized Downlink of a MC-CDMA System

The main purpose of this elaboration is to determine the optimal powers of mobile users in a multi-carrier CDMA (MC-CDMA) system receiving data from a base station (BS). The downlink transmission is pre-equalized and the utility function is a generalized energy efficiency (EE) based on a cross-layer approach and taking into account the presence of a queue. We rely on game theory as a mathematical tool by considering a non-cooperative game whose equilibrium point is called Nash equilibrium (NE) defining the optimal powers. Accordingly, we developed a distributed algorithm aiming at determining this equilibrium. When the subcarriers number increases, important interference is then introduced. In such case, we showed that the social welfare (sum of utilities of all users) decreases while powers at NE increase. In addition, we deduced that a good choice of the consumed power leads to minimize the individual power and maximize the utility at the NE. Moreover, we noticed that when the packet arrival rate increases, the considered generalized EE can be maximized compared to the conventional EE approach while the power at the NE can be minimized. Therefore, we contribute to improve globally the system performances in terms of social welfare, individual utility function and individual power.

Pseudonyms in IPv6 ITS Communications: Use of Pseudonyms, Performance Degradation, and Optimal Pseudonym Change

IPv6 developed as a next generation Internet protocol will provide us with safer and more efficient driving environments as well as convenient and infotainment features in cooperative intelligent transportation systems (ITS). In this paper, we introduce the use of pseudonyms in IPv6 ITS communications for preserving location privacy. We conduct qualitative study on the performance degradation due to the use of pseudonyms and quantitative analysis on the optimal pseudonym change interval. Numerical results demonstrate that an appropriate pseudonym change interval should be changed depending on the packet arrival rate, mobility rate, and security level.

English

Wireless devices are increasing the computing, storage resources and increasing in supporting mobile computing techniques. Particularly, ad hoc networks can potentially connect different wireless devices. The dynamic nature of Vehicular ad hoc networks demands new set of networking strategies to be implemented in order to provide efficient Intelligent Transport System communication. The entire network is mobile and the individual terminals are allowed to move freely. The nodes may be located in or on airplanes, ships, trucks, cars, even on people or very small devices. Routing is a big problem in Vehicular Ad hoc Network; many protocols have been proposed to increase efficiency and security of traditional protocols in VANET. Centralized and distributed scheduling algorithms, use Secure and Efficient data Transmission algorithm have two protocols called SET-IBS (SET Identity Based digital Signature) and SET-IBOOS (SET Identity Based Online/Offline digital Signature). For source to destination calculate this Shortest Path by using this algorithm and another reason is that to save its battery power using centralized and distributed routing. Routing models carry out based on the travelling node should identify the message authenticated on both online and offline, to provide the efficiency and security in the routing models. It based on throughput improvement with the variation of node density such as link failure ratio, packet arrival rate, retransmission threshold. The efficiency in Vehicular Ad hoc Network, to enhance the security provides for misbehaving node detection that integrates security mechanism to prevent unauthorized access for data transmission.

Weighted Round Robin and Rate Limiter based Fair Queuing for WRR

In this paper we present a new packet scheduling method based on parallel usage of multiple WRR schedulers, rate limiters and output bandwidth calculation for modern NGN networks. The main idea of the presented method is to provide queueing fairness within queues. The method provides the same results in output bandwidth allocation as the compared algorithm, while within one queue flows with different packet size and arrival rates gets the same output bandwidth. With this method we are able to achieve the overall result of bandwidth assignment as algorithms like WRR, WFQ, WRRPQ and LLQ by only changing the mathematical model used to calculate the bandwidth assignment. We call this method Weighted Round Robin and Rate Limiter based Fair Queuing (WRRRLbFQ). We prove the model outcome with simulation results using NS2 simulator and compare the behavior with the WRR scheduler.

Analysis of the local delay with slotted-ALOHA based cognitive radio ad hoc networks

We analyze the local delay of cognitive radio ad hoc networks in which secondary nodes are overlaid with a pair of primary nodes. Supposing slotted ALOHA multiple access is adopted by secondary nodes, we derive the closed-form expression of the local delay by modeling the channel occupied by primary nodes as continuous-time Markov on-off process. Furthermore, we obtain the asymptotic local delay for two special cases: large and small primary traffic. We theoretically prove that the local delay increases with the increasing primary packet arrival rate and decreases with the increasing primary packet departure rate. Numerical and simulation results show that the local delay could be approximated to be the result obtained with significant primary traffic in most cases, which is the steady of the channel idle state.

Generation and characterization of orthogonal FH sequences for the cognitive network

The existing orthogonal frequency hopping (FH) sequence cannot support the high throughput and high spectrum efficient cognitive FH (CFH) network due to its small family size, high computational complexity and short period. To overcome these disadvantages, this paper investigates the generation of the orthogonal FH sequence and analyzes its multiple accessibility performance based on the CFH frequency division multiple-access (FDMA) network model. By the random mapping and cyclical shift replacement (CSR) scheme, a large family size of orthogonal FH sequence with dynamic frequency slot number is generated. In this case, the external interference could be eliminated by avoiding the interfered frequencies, and blocking mutual interference incurred for the packet by the orthogonal frequencies. Moreover, the theoretical relationships of the throughput and transmission delay with respect to the user number and the packet arrival rate are given, which shows that our proposed orthogonal FH sequence could support high throughput and short packet transmission delay in CFH-FDMA network. The simulation results validate our theoretical analysis of the CFH-FDMA network performance, and show that our proposed sequence outperforms the widely used no hit zone FH sequences in terms of uniformity, randomness, Hamming correlation, complexity and sensitivity, etc.

Clock Synchronization in Wireless Sensor Networks: Analysis and Design of Error Precision Based on Lossy Networked Control Perspective

Motivated by the importance of the clock synchronization in wireless sensor networks (WSNs), due to the packet loss, the synchronization error variance is a random variable and may exceed the designed boundary of the synchronization variance. Based on the clock synchronization state space model, this paper establishes the model of synchronization error variance analysis and design issues. In the analysis issue, assuming sensor nodes exchange clock information in the network with packet loss, we find a minimum clock information packet arrival rate in order to guarantee the synchronization precision at synchronization node. In the design issue, assuming sensor node freely schedules whether to send the clock information, we look for an optimal clock information exchange rate between synchronization node and reference node which offers the optimal tradeoff between energy consumption and synchronization precision at synchronization node. Finally, simulations further verify the validity of clock synchronization analysis and design from the perspective of synchronization error variance.

Optimal Stochastic Policies in a Network Coding Capable Ad Hoc Networks

Network coding is a promising technology that increases system throughput by reducing the number of packet transmissions from the source node to the destination node in a saturated traffic scenario. Nevertheless, some packets can suffer from end-to-end delay, because of a queuing delay in an intermediate node waiting for other packets to be encoded with exclusive or (XOR). In this paper, we analyze the delay according to packet arrival rate and propose two network coding schemes, iXOR (Intelligent XOR) and oXOR (Optimal XOR) with Markov Decision Process (MDP). They reduce the average delay, even under an unsaturated traffic load, through the Holding-χ strategy. In particular, we are interested in the unsaturated network scenario. The unsaturated network is more practical because, in a real wireless network, nodes do not always have packets waiting to be sent. Through analysis and extensive simulations, we show that iXOR and oXOR are better than the Distributed Coordination Function (DCF) without XOR (the general forwarding scheme) and XOR with DCF with respect to average delay as well as delivery ratio.

ACK-based adaptive backoff for random access protocols

In contention-based networks, ALOHA and CSMA are the most popular random access protocols, wherein a station transmits packets after a certain delay according to a particular backoff policy, such as binary exponential backoff (BEB). When a contention-based network is heavily loaded, system performance, in terms of transmission success rate and throughput, degrades dramatically under random backoff policies without considering the backoff choices of the neighborhood. To alleviate this problem, we propose and verify in this paper a highly efficient backoff policy, namely "ACK-based adaptive backoff " (AAB), which takes into account the total number of successful packet transmissions (with ACKs) among neighboring stations in determining a station's subsequent backoff period before its next packet (re)transmission. By doing this, AAB can effectively reduce the overall packet collisions under heavy-loaded conditions, even with hidden-stations. On comparing with BEB and its modified policy, multiple increase linear decrease (MILD), AAB can achieve about 17% and 10% performance gains of transmission success rate under CSMA protocol in a network with 20 stations with new packet arrival rate of 0.9, and 43% and 16% performance gains of energy efficiency respectively when the former two protocols reach their saturated points.

Delay-Aware Medium Access Schemes for WSN-Based Partial Discharge Measurement

Wireless sensor networks (WSNs) are widely preferred measurement and monitoring tools for a large variety of industrial and environmental applications thanks to their low-cost, energy-efficiency, flexibility, and ease of deployment. However, the use of WSNs for measuring and monitoring industrial applications generating data at high rates, such as online monitoring of partial discharge activities in high voltage equipment in the power grid, presents a significant challenge for the system operators. In such applications, packet arrival rates could increase rapidly due to the occurrence of cascaded faults in the monitored environment. The WSNs with multihop topologies could experience excessive delays and an increase in packet drop of vital data due to the overwhelming increase in the packet arrival rates. Therefore, there should be an optimum operating point of the network where high packet arrival rates and low latency can be maintained at the same time. Thus, there is an immediate need for carefully designed quality of service (QoS) differentiation schemes that can guarantee the delivery of critical data with minimum latency and least loss. In this paper, we present a QoS differentiation scheme for high priority data in multihop WSNs based on an optimization scheme. Analytical and simulation results show that our proposed scheme significantly reduces the delay while maintaining high data delivery ratios and energy efficiency of the network.

Statistical method for performance analysis of WBAN in time-saturation

Performance analysis of carrier sense multiple access with collision avoidance (CSMA/CA) scheme based on IEEE 802.15.6 standard has been discussed in many literatures. In previous works on IEEE 802.15.6 and another standards, the performance was analyzed by using access probability in one slot duration and the Markov chain model was proposed to calculate the access probability in both saturation and non-saturation models. However, for both saturation and non-saturation models, the access probability or the packet arrival rate was assumed to be fixed and the effect of remained packets that was transmitted unsuccessfully due to busy channel or collision was not considered. In this paper, in order to evaluate the system performance more accurately, the effect of the remained packet is taken into account and a statistical method is proposed to calculate the successful probability of wireless body area networks (WBANs). Moreover, a time-saturation model is defined as a system model in which the system performance is changed following the operating time, and then, the change between three models, i.e., saturation, non-saturation, and time-saturation models, is analyzed. The calculation result indicates that the proposal method can achieve the same performance as the Markov chain method in both saturation and non-saturation models. However, in the time-saturation model, the proposal statistical method is more accurate.

Stability Analysis of <inline-formula> <tex-math notation="TeX">$p$</tex-math></inline-formula>-Persistent Slotted CSMA Systems With Finite Population

When multiple users are communicating with an access point based on a random access, the stability region is known as all possible combinations of the mean packet arrival rates to keep their queue lengths bounded. This paper investigates the stability region of $p$ -persistent carrier sense multiple access (CSMA) systems, where two users have different mean packet arrival rates and (re)transmission probabilities. We then extend our results to $p$ -persistent CSMA systems with $N$ users and discuss applicability of our results to IEEE 802.11 systems with the basic and request-to-send/clear-to-send access mechanisms. In numerical studies, we show the stability region by varying system parameters such as packet arrival rates, (re)transmission probabilities, and radio channel errors, and how the stability region of $p$ -persistent CSMA systems gets close to that of a time-sharing system.

Numerical analysis of the power saving with a bursty traffic model in LTE-Advanced networks

We analyze the power saving operation called Discontinuous Reception (DRX) with a novel bursty packet arrival model in 3GPP Long Term Evolution (LTE)-Advanced networks. Typical analytical studies on the power saving operations in wireless networks have been carried out under the assumption that an expectation of exponentially distributed packet arrival intervals stays unchanged. However, practical packet arrival rate may change depending on time or typical Internet services may incur bursty packet arrivals. In either case, we need to evaluate the performance of the DRX operation. For this purpose, we develop a more realistic traffic arrival model considering packets may arrive in a bursty manner under the DRX operation. We, then, analyze the performance of the DRX operation in terms of power saving efficiency and average queuing delay, respectively. The analytical results are validated via comparisons with simulation results.