Multiaccess Protocol Research Articles

Noncoherent Massive Random Access for Inhomogeneous Networks: From Message Passing to Deep Learning

Massive machine-type communications (mMTC) are expected to support a large amount of randomly deployed users for short package transmissions. Noncoherent random access provides an efficient and practical multi-access protocol for mMTC, and also poses new challenges for the receiver design. In this paper, we leverage two well-known methods, i.e., message passing and deep learning, to jointly detect the user activity and the desired data for the noncoherent mMTC. First, by exploiting the exact distribution information of the received signal, a generalized approximate message passing (GAMP)-based algorithm is proposed, which is shown to jointly detect the user activity and the desired data by two modules: inter-user interference elimination and data detection for each user. Inspired by the two-module GAMP-based algorithm, we then propose a model-driven deep learning method, which utilizes the deep neural networks (DNNs) to approximate both the two modules. The loss function for training the DNNs is derived by formulating the two-module detection as an unconstrained optimization problem. Simulation results reveal that the proposed GAMP-based algorithm outperforms the proposed deep learning method when the channel distribution is perfectly known, while it suffers from a significant performance degradation for the case with imperfect channel distribution information.

New Reservation Multiaccess Protocols for Underwater Wireless Ad Hoc Sensor Networks

In a wireless network, where propagation delay is high and communications are sporadic, some kind of reservation protocol is generally used. Reservation access protocols were proposed earlier in earth stations-to-satellite communication with known propagation delay. However, optimality of the number of access slots with respect to the system performance parameters, such as system utilization, blocking probability, and delay, were not thoroughly studied. Besides, the effect of propagation delay uncertainty, which predominantly happens in underwater communications, are yet to be addressed. In this paper, we first analyze the system performance in many-to-one multiaccess data transfer scenario in underwater wireless ad hoc sensor networks with a fixed number of access slots and with the assumption of perfect propagation delay information. We propose two system state aware dynamic approaches to suitably adjust the number of access slots, and investigate the optimum slotting strategy to maximize the system utilization. Next, by accounting the propagation delay uncertainty, we relook into the optimality criteria on the number of access slots, where we apply a modified receiver-synchronized slotted Aloha principle to maximize the access performance. Via mathematical analysis, supported by discrete event simulations, we show that the system utilization and blocking probability performances with our proposed dynamic reservation protocols are consistently better compared to the competitive reservation protocols with fixed as well as variable access slots. Further, we conduct NS3 simulations to study the protocol performances under more realistic channel and traffic conditions, which also demonstrate that the proposed optimized dynamic slotting offers a much better system utilization performance compared to a similar underwater reservation multiaccess protocol.

The Throughput Analysis of IBTCRPP-CSMA in Ad Hoc Network

From the point of view to improve QoS of Ad Hoc network, this paper analyses the problem about mobile nodes in Ad Hoc network and decides to solve the problem by designing effective MAC protocol. Therefore, a novel random multi-access protocol using Binary Tree Collision Resolution for collision packets in Probability-Persistent Random Multi-Access (IBTCRPP-CSMA) is proposed. The throughput of IBTCRPP-CSMA and computer simulation experiments are obtained. Simulation results agree with theoretical analysis. By contrasts of throughputs among several CSMA protocols, IBTCRPP-CSMA has higher throughput and channel utilization, thereby ensuring the system’s high QoS.

CSMA/CA Protocol for Wireless Sensor Network Based on Probability Function Detection

This paper mainly analyzes a type of wireless sensor network MAC protocol based on probability function detection with random multi-access protocol to ensure a higher systemic throughput and stability by using channel load equilibrium. By using the average cycle method, we get the mean waiting time of information packet, the formulas of performance index of the systemic throughput, and the life cycle of node through mathematical derivation strictly. At last, gives the simulation results.

Analysis of Multi-Access MAC Protocol Based on Probability Detection and Non-Persistent for Wireless Sensor Network

This paper presented a new CSMA protocol, which is named probability detection and non-persistent joint control for multi-channel random multi-access (PDNMRM). Throughput of system, throughput of different priority and packet delay are presented by theoretical calculations. The protocol controls the number of sleep node by choosing the value of p, and control system to sleep in idle period. By giving an analysis of energy efficiency of PDNMRM, we got the result that PDNMRM has longer life cycle. Then, the paper proved that theoretical analysis is correct by simulation experiment.

Selfish users in energy constrained ALOHA systems with power capture

We consider a slotted ALOHA setting where backlogged, energy-constrained users selfishly select the probability with which they transmit packets. Packets are successfully received, even in case of collision, if the signal to interference plus noise ratio at the access point exceeds some threshold (power capture). The user problem of finding appropriate transmission probabilities is formulated as a static non-cooperative game and the performance limits for stationary and mobile scenarios are determined. The equilibrium analyses show that for stationary scenarios, users with high pathgains share the channel fairly while others never transmit. In the mobile case users utilize a binary strategy where they try to monopolize the channel when their pathgain exceeds some threshold that depends on system parameters (number of users, transmission costs, etc.). Otherwise they shut their transmitters off. Compared to traditional nondiscriminatory distributed multiaccess protocols the operating points achieved by selfish users generally increase sum-utility although this comes at the expense of larger user performance variations.

Protocol design and throughput analysis for multi-user cognitive cooperative systems

This paper deals with protocol design for cognitive cooperative systems with many secondary users. In contrast with previous cognitive configurations, the channel model considered assumes a cluster of secondary users which perform both a sensing process for transmitting opportunities and can relay data for the primary user. Appropriate relaying improves the throughput of the primary users and can increase the transmission opportunities for the cognitive users. Based on different multi-access protocols, the schemes investigated enable relaying either between the primary user and a selected secondary user or between two selected secondary users. This collaboration can be a simple distributed multiple-input single-output transmission of the primary data or a simultaneous transmission of primary and secondary data using dirty-paper coding (DPC). The parametrization of DPC as well as its combination with opportunistic relay selection yields an interesting trade-off between the primary and the secondary performance which is investigated by theoretical and simulation results under the perspective of a desired primary throughput. The proposed protocols are studied from a networking point of view and the stable throughput for primary and secondary users is derived based on the principles of queueing theory.

Analysis of Multi-Channel and Slotted Random Multi-Access Protocol with Two-Dimensional Probability for Ad Hoc Network

A higher quality of service (QoS) is provided for ad hoc networks through a multi-channel and slotted random multi-access (MSRM) protocol with two-dimensional probability. For this protocol, the system time is slotted into a time slot with high channel utilization realized by the choice of two parameters p 1 and p 2, and the channel load equilibrium. The protocol analyzes the throughput of the MSRM protocol for a load equilibrium state and the throughput based on priority. Simulations agree with the theoretical analysis. The simulations also show that the slotted-time system is better than the continuous-time system.

Markovian receiver collision analysis of high-speed multi-channel networks

Two synchronous transmission multi-channel multi-access protocols for high-speed network architecture are studied in this paper. Analytic discrete time Markovian models are developed for finite number of stations and finite number of channels for the symmetric and asymmetric access rights proposed protocols. The effect of receiver collision phenomenon is examined and analysed on the performance measures evaluation and estimated by the probability of packet rejection at destination. Also, numerical results are presented for comparison for various numbers of data channels and stations. Copyright © 2005 John Wiley & Sons, Ltd.

Performance evaluation of a new multiaccess protocol for local area networks

A new self-adaptive protocol for broadcast networks, capable of operating efficiently under bursty traffic conditions and allowing stations to transmit packets of variable length, is introduced. Fixed-assignment protocols such as TDMA have known drawbacks, which are resolved by learning protocols such as LTDMA. However, the fact that LTDMA uses fixed-sized timeslots can result in network equipment overloading as well as wasted timeslots and reduced channel usage. The proposed Variable Packet Length/LTDMA protocol is tested by using real LAN traffic traces and it is proved that it successfully resolves the above issues and achieves a high throughput-delay performance when operating under realistic traffic conditions.

Optimal capacity of p-persistent CSMA protocols

We deal with the characterization and computation of the p value, say p/sub opt/, corresponding to the maximum protocol capacity in p-persistent carrier-sense multiaccess (CSMA) protocols. The contribution of this paper is twofold. First, we give an analytical justification, and a numerical validation of a heuristic formula widely used in the literature to characterize the p/sub opt/. Second, we provide closed formulas for the p/sub opt/, and we show that the optimal capacity state, given the message length distribution, is characterized by an invariant figure: the Mp/sub opt/ product.

Performance evaluation of a new multiaccess protocol for local area networks

A new self-adaptive protocol for broadcast networks, capable of operating efficiently under bursty traffic conditions and allowing stations to transmit packets of variable length, is introduced. Fixed-assignment protocols such as TDMA have known drawbacks, which are resolved by learning protocols such as LTDMA. However, the fact that LTDMA uses fixed-sized timeslots can result in network equipment overloading as well as wasted timeslots and reduced channel usage. The proposed Variable Packet Length/LTDMA protocol is tested by using real LAN traffic traces and it is proved that it successfully resolves the above issues and achieves a high throughput-delay performance when operating under realistic traffic conditions.

Design, performance and wavelength assignment of a wavelength division multiaccess protocol for optical fibre ring networks

This paper presents a multiaccess strategy for use over optical fibre ring networks employing two counter rotating rings, and using wavelength division multiplexing. Transmitters employ tunable lasers, while receivers employ one or more fixed wavelength filters. The paper introduces an algorithm for the optimal assignment of the receivers to the channels, such that the possibility of finding an unused channel leading to a certain receiver is maximized. The paper contains a performance study of the network protocol.

A multi-access technique for broadband wireless local networks

This paper presents a new multi-access technique that allows multimedia information to be transported in indoor wireless networks. Growing emphasis on multimedia calls for the development of multi-access protocols capable of supporting demanding applications such as audio/video playback, image browsing, real-time voice/video transmission and interactive data exchange in a unified manner. To this end, a practical multi-access scheme called `reserved polling' is proposed. The technique handles a diverse mixture of delay classes and message priorities associated with multimedia traffic with an inherent ability to adapt to the traffic load profile. In order to gain a quantitative insight into its behavior, the protocol is analyzed and simulated in detail.

Enhanced reserved polling multiaccess technique for multimedia personal communication systems

This article describes a multiaccess technique which allows the transport of multimedia information across global personal communication systems (PCS). Impressive growth in the application of wireless technologies to telecommunications has sparked active research on a new generation of mobile radio networks projected to handle heterogeneous traffic types. One of the key requirements of these advanced systems is the multiaccess protocol which must guarantee quality of service and provide efficient access to multirate broadband applications that combine voice, video and data communications. In addition, the protocol is required to operate with the demanding constraints imposed by moving users, dynamic traffic load variations and highly sensitive wireless links. To this end, a multiaccess scheme called “enhanced reserved polling” is proposed. The scheme is designed to execute many PCS-related functions including radio resource assignment, connection control and mobility management. It accommodates a diverse mixture of delay classes/message priorities and can also enhance the bandwidth sharing among different cells in the network.

PAMAS—power aware multi-access protocol with signalling for ad hoc networks

In this paper we develop a new multiaccess protocol for ad hoc radio networks. The protocol is based on the original MACA protocol with the adition of a separate signalling channel. The unique feature of our protocol is that it conserves battery power at nodes by intelligently powering off nodes that are not actively transmitting or receiving packets. The manner in which nodes power themselves off does not influence the delay or throughput characteristics of our protocol. We illustrate the power conserving behavior of PAMAS via extensive simulations performed over ad hoc networks containing 10-20 nodes. Our results indicate that power savings of between 10% and 70% are attainable in most systems. Finally, we discuss how the idea of power awareness can be built into other multiaccess protocols as well.

Information theory and communication networks: an unconsummated union

Information theory has not yet had a direct impact on networking, although there are similarities in concepts and methodologies that have consistently attracted the attention of researchers from both fields. In this paper, we review several topics that are related to communication networks and that have an information-theoretic flavor, including multiaccess protocols, timing channels, effective bandwidth of bursty data sources, deterministic constraints on datastreams, queuing theory, and switching networks.

Real-time communications using TDMA-based multi-access protocol

In this paper, we study first the performance issues, especially message sojourn time and message overflow, of the TDMA protocol and then show how to use these results to design protocol parameters in order to meet the soft real-time requirements. We consider a single queue with multiple output ( b messages) and finite buffer capacity (denoted by K), K and b being two protocol parameters that a designer can choose. Assuming Poisson fixed-length message arrivals, the exact expressions for the distribution function of the message sojourn time and the overflow probability are derived. It has been shown that these results can be applied to various particular cases (e.g. the infinite buffer capacity case) and therefore appear as a versatile solution for TDMA schemes. Moreover, the monotonicity for the overflow probability is proved, which gives us a theoretical base for the dimensioning task. Using the stated results, the design and implementation of real-time protocols based on TDMA can be achieved. An example is examined emphasizing the choice of the parameters K and b according to time and overflow constraints.

Next-generation multiservice VSAT networks

Very-small-aperture terminal (VSAT) satellite networks have so far been successful in the provision of specific communication services to geographically dispersed users. However, user demands are becoming more complex and VSAT networks are expected to provide a much wider range of services (voice, data and multimedia). This paper investigates how this service integration could be achieved and shows that performance improvements are possible if efficient multi-access protocols and speech compression with voice-activity-detection techniques are used. It also discusses the future role that VSATs could play in the provision of access to the integrated broadband communication network to remote users. It is shown that it could be possible to use VSATs for ATM service provision, but there are limitations on the system's performance from the satellite delay and limited link capacity.

Maximization of the channel utilization in wireless heterogeneous multiaccess networks

The key aspect of personal communication services (PCS) is wireless access through local and wide area networks where there may exist a variety of services having different rates and diverse quality-of-service (QOS) requirements. This paper addresses the problem of maximizing the channel utilization in a wireless heterogeneous network with finite population. Slotted ALOHA with packet capture is used as the multiaccess protocol in the presence of background noise and Rayleigh fading. It is known that the capture effect, while significantly increasing the network throughput, causes unfairness among users in a heterogeneous network. To take fairness into consideration, individual throughput is used as the constraint with the channel utilization being the maximization objective. The maximization problem is then studied under various conditions by controlling the transmission power and/or probability. It is shown that for a narrow-band system under equal individual throughput requirement, transmission probability control is more effective than power control, and when a joint control strategy is employed, perfect or near perfect channel utilization can be achieved in the absence or presence of Rayleigh fading.