Average Packet Transmission Delay Research Articles

Signal transmission diversity based successive interference cancellation-slotted aloha

Efficient medium access protocols are crucial in leveraging the advancement in the physical layer techniques that have been proposed for the next-generation wireless networks. However, collisions among data packets in random access protocols reduce channel efficiency and hence the throughput. In this paper, we propose a MAC protocol based on both the signal transmission diversity and Successive interference cancellation (SIC) to improve the throughput. In the proposed Medium Access Control (MAC) protocol, the receiver receives two sets of signals from the transmitters over two uncorrelated time slots. Inter slot SIC is first carried out at the receiver over two independent sets of received interfered signals. Signals are decoded by canceling those signals that have already been decoded in one set from the other set. Closed-form expressions for the packet decoding probability, system throughput, average packet transmission delay, and energy efficiency have been derived by considering order statistics of received signal power. Analytical results are validated against simulation. Maximum achievable throughput of the proposed scheme is shown to be four times that of slotted Aloha and twice that of a slotted Aloha with SIC.

Analysis of discontinuous reception (DRX) on energy efficiency and transmission delay with bursty packet data traffic

Discontinuous reception (DRX) is a way for user equipment (UE) to save energy. DRX forces a UE to turn off its transceivers for a DRX cycle when it does not have a packet to receive from a base station, called an eNB. However, if a packet arrives at an eNB when the UE is performing a DRX cycle, the transmission of the packet is delayed until the UE finishes the DRX cycle. Therefore, as the length of the DRX cycle increases, not only the amount of UE energy saved by the DRX but also the transmission delay of a packet increase. Different applications have different traffic arrival patterns and require different optimal balances between energy efficiency and transmission delay. Thus, understanding the tradeoff between these two performance metrics is important for achieving the optimal use of DRX in a wide range of use cases. In this paper, we mathematically analyze DRX to understand this tradeoff. We note that previous studies were limited in that their analysis models only partially reflect the DRX operation, and they make assumptions to simplify the analysis, which creates a gap between the analysis results and the actual performance of the DRX. To fill this gap, in this paper, we present an analysis model that fully reflects the DRX operation. To quantify the energy efficiency of the DRX, we also propose a new metric called a real power-saving (RPS) factor by considering all the states and state transitions in the DRX specification. In addition, we improve the accuracy of the analysis result for the average packet transmission delay by removing unrealistic assumptions. Through extensive simulation studies, we validate our analysis results. We also show that compared with the other analysis results, our analysis model improves the accuracy of the performance metrics.

Signaling Packet Aggregation and Compression in SIP Network: Modeling and Performance Evaluation

Recent development in communications have increased the demand of internet protocol (IP)-based multimedia conferencing services. Session initiation protocol (SIP) is a signaling protocol used for providing group communication in IP-based next generation network. The conferencing frameworks proposed by Internet Engineering Task Force working groups has limited scalability due to the centralized management of conference control by a single server. In order to overcome this limitation, we propose multiple SIP packet aggregation and compression of common header part of each aggregated packet process. This mechanism increases the bandwidth utilization and processing capability of conference server. A queueing model is developed to describe the process of packet aggregation (PA) and compression at the edge proxy. Using the proposed queueing model, the steady-state probability distribution of the queue length is derived and the average packet transmission delay is obtained. We show the trade-off between the overhead gain and delay. Based on the analytical results, the maximum frame size is optimized for which the average delay of a packet transmission is minimum. A discrete event simulation is performed using network simulator 2 to implement PA and compression mechanism in a SIP network. Further, performance measures are numerically obtained from the simulation results. The simulation results discussed upon the key performance metrics for signaling protocols defined by the International Telecommunication Union (ITU) Telecommunication Standardization Sector (ITU-T E.721).

Performance Analysis of Multiple Relays Cooperative Truncated Automatic Repeat Request in Wireless Sensor Networks

In this paper, we research the performance of direct and non-direct multiple relays cooperative truncated automatic repeat request (D/ND-MRCT-ARQ) protocols in wireless sensor networks (WSNs). We propose a method that named discrete time Markov chain (DTMC) with N + 2 states, which could obtain the throughput formulas of D/ND-MRCT-ARQ protocols. Furthermore, we solve the mathematical expressions of the average transmission delay of both protocols by truncating the number of packet retransmission. In addition, we derive energy efficiency formulas of both protocols under considering the different power consumption of each node. Simulation results demonstrate that the proposed D-MRCT-ARQ protocol achieve higher throughput and energy efficiency while fewer average packet transmission delay, as compared with the ND-MRCT-ARQ protocol.

Performance Analysis of a Novel Distributed C-ARQ Scheme for IEEE 802.11 Wireless Networks

It is well-known that the cooperative communication and error control technology can improve the network performance, but most existing cooperative MAC protocols have not focused on how to cope with the contention process caused by cooperation and how to reduce the bad influence of channel packet error rate on the system performance. Inspired by this, this paper first modifies and improves the basic rules of the IEEE 802.11 Medium Access Control (MAC) protocol to optimize the contention among the multi-relay in a cooperative ARQ scheme. Secondly, a hybrid ARQ protocol with soft combining is adopted to make full use of the effective information in the error data packet and hence improve the ability of the receiver to decode the data packet correctly. The closed expressions of network performance including throughput and average packet transmission delay in a saturated network are then analyzed and derived by establishing a dedicated two-dimensional Markov model and solving its steady-state distribution. Finally, the performance evaluation and superiority of the proposed protocol are validated in different representative study cases through MATLAB simulations.

The impact of the superposition coding concept on admission control strategy in OFDMA-based network

Admission control is a key mechanism to manage the increasing number of the simultaneous demanding services, requiring a desired Quality of Service (QoS) in a spectrum efficient manner. To address this issue, we investigate in this work, the use of the superposition coding technique to increase the system capacity through multiuser diversity exploitation. We propose a novel joint admission control and superposition coding formalism based on different utility functions: Opportunistic (OPSC), Great Fairness (GFSC) and Proportional Fairness (PFSC). Simulation results show the superiority of our proposed approaches over other by providing higher mean of served VoIP users and higher throughput while maintaining an average VoIP packet transmission delay lower than 0.6 ms.

Improving Common Control Channel Capacity and Performance for Cognitive Radio Networks

Cognitive radio (CR) is a promising solution to cope with the inefficient usage of the frequency spectrum. CR lets its users leverage empty or idle parts of spectrum opportunistically. The medium access control (MAC) sub-layer in CR based networks is playing a crucial role in controlling user’s access to the shared medium and their interaction with Primary Users as well. Coordination and controlling users’ access to common control channel (CCC) at MAC sublayer can be a challenging issue in this type of networks. High availability of this channel is very important and crucial, so designing a mechanism which contributes to this, is of great importance. The CCC’s limited capacity alongside a large number of contending nodes for it causes channel saturation and consequently, leads to its unavailability. The paper introduces a useful method to compute supported saturation capacity of the CCC. It also introduces a new access mode for CCC called “Channelization”, to improve saturation capacity for it. The effect of “Channelization” scheme is also investigated on average packet delay, and according to it desirable parameters for channelization is calculated. Analytical analysis alongside simulation result shows that the channelization method can have a great impact on the increasing saturation capacity, and lower average packet transmission delay.

Performance analysis and saturation bound research of cyclic-quorum multichannel MAC protocol based on Markov chain model

In high diversity node situation, single-channel MAC protocols suffer from many collisions. To solve this problem, the research of multichannel MAC protocol has become a hotspot. And the cyclic quorum-based multichannel (CQM) MAC protocol outperformed others owing to its high frequency utilization. In addition, it can avoid the bottleneck that others suffered from and can be easily realized with only one transceiver. To obtain the accurate performance of CQM MAC protocol, a Markov chain model, which combines the channel hopping strategy of CQM protocol and IEEE 802.11 distributed coordination function (DCF), is proposed. The metrics (throughput and average packet transmission delay) are calculated in performance analysis, with respect to node number, packet rate, channel slot length and channel number. The results of numerical analysis show that the optimal performance of CQM protocol can be obtained in saturation bound situation. And then we obtain the saturation bound of CQM system by bird swarm algorithm (BSA). Finally, the Markov chain model and saturation bound are verified by Qualnet platform. And the simulation results show that the analytic and simulation results match very well.

Analysis of dual-hop and multiple relays cooperative truncated ARQ with relay selection in WSNs

The dual-hop truncated ARQ (DHT-ARQ) and multiple relays cooperative truncated ARQ (MRCT-ARQ) with relay selection in wireless sensor networks are analytically analyzed in this paper. A three-state discrete time Markov chain method is proposed, which is then used to derive the steady state distribution and throughput expressions. Furthermore, the number of retransmission of the two protocols is truncated, and the average packet transmission delay is solved. Finally, considering the power consumptions of source node, relay node and destination node, the energy efficiency expressions are obtained. Numerical simulation results show that the throughput and delay performance of the latter is better than the former. When the channel environment becomes poor, using the DHT-ARQ protocol is more advantageous to reduce system overhead.

Power allocation and transmission scheduling for a network with bidirectional relaying links

AbstractIn this paper, we study packet transmission scheduling for a network with bidirectional relaying links, where the relay station can use network coding to combine packets to multiple receivers and opportunistically decide the number of packets to be combined in each transmission. Two cases are considered, depending on whether nodes are allowed to overhear transmissions of each other. A constrained Markov decision process is first formulated with an objective to minimize the average delay of packet transmissions, subject to the maximum and average transmission power limits of the relay node. The complexity for solving the constrained Markov decision process (MDP) is prohibitively high, although the computational complexity for the no‐overhearing case can be greatly reduced. Heuristic schemes are then proposed, one applies to the general case, and another applies to only the no‐overhearing case. Numerical results demonstrate that the heuristic schemes can achieve close‐to‐optimum average packet transmission delay, and furthermore, the second scheme achieves lower maximum delay while keeping the same average packet transmission delay and relay node power consumption as the first one. Copyright © 2015 John Wiley & Sons, Ltd.

On the Performance of Overlaid Wireless Sensor Transmission with RF Energy Harvesting

RF energy harvesting is a promising potential solution for providing convenient and perpetual energy supply to low-power wireless sensor networks. In this paper, we investigate the performance of overlaid wireless sensor transmission powered by RF energy harvesting from existing wireless system. Specifically, we derive the exact closed-form expression for the distribution function of harvested energy over a certain number of channel coherence time over Rayleigh fading channels with the consideration of hardware limitation, such as energy harvesting sensitivity and harvesting efficiency. We also obtain the exact distribution of the number of coherence time needed for fully charging the sensor. Based on these analytical results, we analyze the average packet delay and packet loss probability of sensor transmission subject to interference from existing system, for delay insensitive traffics and delay sensitive traffics, respectively. Finally, we investigate the optimal design of energy storage capacity of the sensor nodes to minimize the average packet transmission delay for delay insensitive traffics with two candidate transmission strategies.

Analytical average throughput and delay estimations for LTE uplink cell edge users

Estimating average throughput and packet transmission delay for worst case scenario (cell edge users) is crucial for LTE cell planners in order to preserve strict QoS for delay sensitive applications. Cell planning techniques emphasize mostly on cell range (coverage) and throughput predictions but not on delay. Cell edge users mostly suffer from throughput reduction due to bad coverage and consequently unexpected uplink transmission delays. To estimate cell edge throughput a common practice on international literature is the use of simulation results. However simulations are never accurate since MAC scheduler is a vendor specific software implementation and not 3GPP explicitly specified. This paper skips simulations and proposes an IP transmission delay and average throughput analytical estimation using mathematical modeling based on probability delay analysis, thus offering to cell planners a useful tool for analytical estimation of uplink average IP transmission.

An adaptive hybrid dynamic power management algorithm for mobile devices

We propose a novel power efficient adaptive hybrid dynamic power management (AH-DPM) algorithm. To adapt well to bursty request arrival patterns with self-similarity and a service provider (SP, i.e., hard disk or WLAN NIC, in this paper) with multiple inactive states, the proposed AH-DPM first derives the average idle time of the SP in the bursty (ON) period and non-bursty (OFF) period separately. Then, to achieve better power saving, we use the average idle time in the ON period to adjust the timeout value more precisely and use the average idle time in the OFF period to decide which inactive state the SP should be switched to. Experimental results based on real traces show that, for the hard disk, the average power consumption of the proposed AH-DPM is better than that of the Adaptive Timeout (ATO), Machine Learning (ML), Predictive, Static Timeout (STO), and Stochastic algorithms. In addition, the average response time of the proposed AH-DPM algorithm is still lower than that specified in a typical hard disk specification. As to the WLAN NIC, experimental results show that the average power consumption of the proposed AH-DPM is comparable to that of the Oracle (theoretically optimal), ATO, and Predictive algorithms, and is better than that of the ML, STO, and Stochastic algorithms. However, the average packet transmission delay of the proposed AH-DPM is better than that of the ATO and Predictive algorithms. Therefore, by providing a better tradeoff between average power consumption and average response time (or average packet transmission delay), the proposed AH-DPM algorithm is very feasible for extending the battery lifetime of ever increasing mobile devices that are equipped with hard disks and WLAN NICs.

A Hybrid Routing Protocol and Performance Evaluation in a Wireless Mesh Network

The size of mesh networks depends upon the usage scenario so that the use of any single routing algorithm alone, either proactive or reactive, may not work efficiently. This letter proposes a hybrid routing algorithm, where a different algorithm is applied depending on the hop count between source and destination nodes. The algorithm allows using a proactive algorithm when a destination is nearby and a reactive algorithm when a destination is away from a source node. In this letter, we adopt the Destination Sequenced Distance Vector routing protocol (DSDV) for a nearby destination and the Ad hoc On-Demand Vector routing protocol (AODV) for a remote destination. A node maintains only a shared routing table for routing protocols, which helps reducing the size of the routing table at a node within a mesh network. Its routing performance is compared to those in DSDV and AODV in terms of normalized routing load, average packet transmission delay, and the average number of entries in the routing table.

Delay Performance Analysis for Supporting Real-Time Traffic in a Cognitive Radio Sensor Network

Traditional wireless sensor networks (WSNs) working in the license-free spectrum suffer from uncontrolled interference as the license-free spectrum becomes increasingly crowded. Designing a WSN based on cognitive radio can be promising in the near future in order to provide data transmissions with quality of service requirements. In this paper we introduce a cognitive radio sensor network (CRSN) and analyze its performance for supporting real-time traffic. The network opportunistically accesses vacant channels in the licensed spectrum. When the current channel becomes unavailable, the devices can switch to another available channel. Two types of channel switchings are considered, in periodic switching (PS) the devices can switch to a new channel only at the beginning of each channel switching (CS) interval, while in triggered switching (TS) the devices can switch to a new channel as soon as the current channel is lost. We consider two types of real-time traffic, i) a burst of packets are generated periodically and the number of packets in each burst is random, and ii) packet arrivals follow a Poisson process. We derive the average packet transmission delay for each type of the traffic and channel switching mechanisms. Our results indicate that real-time traffic can be effectively supported in the CRSN with small average packet transmission delay. For the network using PS, packets with the Poisson arrivals experience longer average delay than the bursty arrivals; while for the network using TS, packets with the bursty arrivals experience longer average delay.

Reservation and Status Sensing Multiple Access Protocol in Slotted CDMA Systems

This paper proposes a medium access control protocol for integrated voice and data services in slotted CDMA systems. The proposed protocol, which is named as RCSSMA (Reservation Code and Status Sensing Multiple Access), adopts a code reservation and status sensing schemes. RCSSMA protocol gives higher access priority to the voice traffic than data traffic for reducing the packet dropping probability. The voice terminal reserves an available spreading code to transmit voice packets during a talkspurt, whereas the data terminal transmits a packet over one of the available spreading codes that are not reserved by the voice terminals. In this protocol, the voice packets never contend with the data packets. Packet dropping probability and average data packet transmission delay are analyzed using a Markov chain model.

Packet Scheduling and Fairness for Multiuser MIMO Systems

This paper investigates the network resource allocation in multiuser downlink wireless systems where the base station and the mobile stations are equipped with multiple antennas to provide fair and efficient transmission services to the mobile users. We focus on packet scheduling, given that it has a significant impact on the overall performance of a multiple-input-multiple-output (MIMO) system. Most previous schedulers designed at the packet level do not take into account the traffic characteristics (different packet lengths and the arrival process parameters); consequently, they fall short of simultaneously providing fairness and a low average packet transmission delay. We are making use of a flexible packet transmission algorithm at the medium access control (MAC) layer to develop and propose a novel scheduler, which is referred to as MIMO packet-based proportional fairness (MP-PF). The new scheduler is designed with the goal of providing high performance in terms of a low average packet transmission delay and time and service fairness among the users based on the concept of proportional fairness. The scheduler also conserves work and takes into consideration the packet length, the user queue length, the user transmission rate (related to its channel quality), and the service guarantees for heterogeneous users. The well-known ideal service fair scheduler called max-min can also significantly be improved using our framework by taking into consideration the traffic characteristics. We also provide an analysis for the fairness of the new scheduler in terms of time and service allocation, which is the key contribution of this paper. Simulations that consider the traffic characteristics and the mobility of users show the relatively low average packet transmission delay and demonstrate the time and service fairness capabilities of MP-PF, compared with other well-known MIMO schedulers.

Medium access control priority mechanism for a DQMAN-based wireless network

The analysis of an access priority mechanism for a high-performance medium access control (MAC) protocol, the distributed queueing MAC protocol for wireless ad hoc networks (DQMAN), is presented in this letter. DQMAN is comprised of a hierarchical, dynamic, and spontaneous master-slave clustering algorithm together with an embedded tree-splitting collision resolution algorithm based on access mini-slots. The responsibility of being master entails extra functionality, and thus extra energy consumption. Therefore, this responsibility must be shared in a dynamic manner among all the stations of the network in order to ensure fairness in the system. By allowing those stations acting as master stations to avoid contention to get access to the channel, their average packet transmission delay can be effectively reduced compared to that of slave stations. Consequently, stations may be encouraged to operate in master mode regardless of the extra functions they may have to carry out. We analyze in this letter the reduced average packet transmission delay for masters.

Packet level performance analysis in wireless user-relaying networks

In this paper, the impact of user relaying on the behavior of a relay node, which acts as the source node at the same time, is analyzed in a wireless relay network at the packet level. The analysis process models the behavior of the relay node as a queueing system and represents the service for its own packet transmission as an M/G/1-type Markov chain. By considering the fact that the maximum number of packet arrivals is ordinarily limited in a practical system, the M/G/1-type Markov chain is further reformatted into a quasi-birth-death (QBD) process through re-blocking so as to simplify the analysis and obtain the associated performance, such as average packet transmission delay. As an application of the results arising from the analysis, a new relay node selection scheme, based on a utility function approach that jointly considers the channel and the queue conditions at the relay node, is proposed. Numerical results show that the proposed analysis model is quite accurate and the proposed relay node selection scheme is effective in balancing cooperative diversity gain and packet transmission delay.

Persistent RCSMA: A MAC Protocol for a Distributed Cooperative ARQ Scheme in Wireless Networks

The persistent relay carrier sensing multiple access (PRCSMA) protocol is presented in this paper as a novel medium access control (MAC) protocol that allows for the execution of a distributed cooperative automatic retransmission request (ARQ) scheme in IEEE 802.11 wireless networks. The underlying idea of the PRCSMA protocol is to modify the basic rules of the IEEE 802.11 MAC protocol to execute a distributed cooperative ARQ scheme in wireless networks in order to enhance their performance and to extend coverage. A closed formulation of the distributed cooperative ARQ average packet transmission delay in a saturated network is derived in the paper. The analytical equations are then used to evaluate the performance of the protocol under different network configurations. Both the accuracy of the analysis and the performance evaluation of the protocol are supported and validated through computer simulations.