CSMA Protocol Research Articles

CSMA Protocol performance with dynamic spreading factor in LPWAN networks with LoRa RF transceivers

Long Range (LoRa) is a spread spectrum modulation technology designed for Low-Power Wide-Area Networking (LPWAN) with a growing application in Internet of Things (IoT), which plays an important role in the global digitalization process. The expansion of LORAWAN networks demands careful circuit, system and network design to improve energy efficiency and quality of service. To support this task, advanced CAD tools can offer reliable network simulations results, where the effects of building blocks can be found. LoRaSim, one of the most popular simulators available for LoRa and LoraWan, had solely implemented an ALOHA access model protocol, which is not the most common protocol in real life scenarios. To mitigate this limitation and taking advantage of the open-source nature of both LoRaWAN and LoRaSim, it is proposed a Carrier Sense Multiple Access/ Collision Avoidance (CSMA/CA) protocol extension, as well as active adaptive parameters selection to cope with collisions. To demonstrate the effectiveness of these additions to the base solution, a comparison between both on different scenarios and their simulated performance key indicators will be presented.

New Multipriority and Variable Duration Triple Time Slot P-CSMA Protocol for Edge Servers Server Deployment

In this paper, we study the joint impact of task priority and transmission time slot variable computing services on a novel p-persistent random multiple access communication protocol (p-persistent CSMA) in an edge server network. The traditional p-persistent CSMA protocol performs better at low loads, and in order to make the protocol perform better even when the edge server network is accessed by a large number of smart terminals, we consider adding a variable success time slot length and a multichannel, multipriority access model. When the success time slot is longer, the nodes will take longer time to send data, which will reduce the number of nodes retransmitting data, thus improving channel utilization and making the throughput rate of the network increase accordingly. Then, different priority levels are assigned according to the user’s needs, and the higher the priority level, the more channels are occupied and the probability of successful message delivery increases. Finally, the superiority of the proposed protocol is verified by simulation.

Unfairness of Random Access with Collision Avoidance in Industrial Internet of Things Networks.

This paper is focused on the analysis of unfairness of random media access in Local Operating Networks (LON), which is one of the commercial platforms of the Industrial Internet of Things (IIoT). The unfairness in accessing the LON channel is introduced by a collision avoidance mechanism in the predictive p-persistent CSMA protocol adopted at the media access control layer. The study on the bandwidth share in predictive p-persistent CSMA calls for the analysis of multiple memoryless backoff. In this paper, it is shown that the channel access in LON systems is unfair in the short term for medium traffic load conditions, and in the long term for heavy loaded networks. Furthermore, it is explained that the average bandwidth allocated to a particular node is determined implicitly by the load scenario, while an actual node bandwidth fluctuates in time according to stochastic dynamics of the predictive p-persistent CSMA. Next, it is formally proven that the average bandwidth available to a node is a linear function of its backoff state and does not depend on backoff states of the other stations. Finally, it is demonstrated that possibly unfair bandwidth share in LON networks determined implicitly by load scenario is stable because, with lowering a fraction of actual network bandwidth accessible by a given station, the probability to decrease it in the future also drops.

High-Performance Long Range-Based Medium Access Control Layer Protocol

Long Range (LoRa) has become one of the most promising physical layer technologies for the Internet of Things (IoT) ecosystem. Although it manifests low-power consumption and long-distance communication, LoRa encounters a large number of collisions in the IoT environment, which severely affects the system’s throughput and delay performance. In this paper, a code division carrier sense multiple access (CD/CSMA) protocol that resolves the traditional channel collision problem and implements multi-channel transmission is proposed for the LoRa medium access control (MAC) layer. To reduce data transmission delay and maximize the throughput of the system, the adaptive p-persistent CSMA protocol divides the channel load into four states and dynamically adjusts the data transmission probability. Then, to reduce channel collisions significantly, the code division multiple access (CDMA) protocol is performed on different channel states. Moreover, the combination of the proposed adaptive p-persistent CSMA protocol and the CDMA successfully reduces the number of data retransmissions and makes LoRa more stable. The simulation results demonstrate that the proposed adaptive p-persistent CD/CSMA protocol can achieve near-optimal and occasionally even better performance than some conventional MAC protocols, especially in a heavy load channel.

ANALYTICAL MODEL OF RANDOM MULTIPLE ACCESS PROTOCOL PREDICTIVE P-PERSISTENT CSMA

Context. New model and quantification method of probable and time characteristics of information-control network with carrier sense random multiple access protocol and predicting network load of predictive p-persistent CSMA had been created. The object of the research was the process of information exchange in Fieldbus-networks LonWorks, BacNet with the analyzed protocol. Objective. The aim of the research is to increase the accuracy of quantitative estimates of the characteristics of time and delivery reliability of information messages in the network with the analyzed protocol. Method. The method of probability theory has been used there to solve the problem of creating a new correct model. The analysis of the functioning principles of the predictive p-persistent CSMA protocol is performed and the parameters influencing its work are set (on the example of the LonTalk stack). A graph of states and transitions of the protocol model describing the principles of transmission of information messages over a network with a software communication medium, considering the allocated significant network and protocol parameters. A method for calculating the graph is offered and new analytical relations are obtained to estimate the main model probabilistic and temporal characteristic: the average delay time of message transmission, the average load of the communication channel, the probability of successful/unsuccessful transmission and data loss in the network. Results. The developed model and method of quantitative assessment of probabilistic and temporal characteristics of data transmission in a network with multiple access protocol predictive p-persistent CSMA. The results are mostly differ from analogs by correct accounting of sporadic and diverse network load by the node delivery services. Conclusions. The held experiments have confirmed the work capacity of the proposed mathematical support and allow to recommend it for solving the assessment characteristics problems of information exchange in the design of analyzed networks with given probabilistic and temporal characteristics.

Temporal starvation in multi-channel CSMA networks

In this paper we consider a stochastic model for a frequencyagile CSMA protocol for wireless networks where multiple orthogonal frequency channels are available. Even when the possible interference on the different channels is described by different conflict graphs, we show that the network dynamics can be equivalently described as that of a single-channel CSMA algorithm on an appropriate virtual network. Our focus is on the asymptotic regime in which the network nodes try to activate aggressively in order to achieve maximum throughput. Of particular interest is the scenario where the number of available channels is not sufficient for all nodes of the network to be simultaneously active and the well-studied temporal starvation issues of the single-channel CSMA dynamics persist. For most networks we expect that a larger number of available channels should alleviate these temporal starvation issues. However, we prove that the aggregate throughput is a non-increasing function of the number of available channels. To investigate this trade-off that emerges between aggregate throughput and temporal starvation phenomena, we propose an analytical framework to study the transient dynamics of multi-channel CSMA networks by means of first hitting times. Our analysis further reveals that the mixing time of the activity process does not always correctly characterize the temporal starvation in the multi-channel scenario and often leads to pessimistic performance estimates.

Temporal starvation in multi-channel CSMA networks: an analytical framework

In this paper, we consider a stochastic model for a frequency-agile CSMA protocol for wireless networks where multiple orthogonal frequency channels are available. Even when the possible interference on the different channels is described by different conflict graphs, we show that the network dynamics can be equivalently described as that of a single-channel CSMA algorithm on an appropriate virtual network. Our focus is on the asymptotic regime in which the network nodes try to activate aggressively in order to achieve maximum throughput. Of particular interest is the scenario where the number of available channels is not sufficient for all nodes of the network to be simultaneously active and the well-studied temporal starvation issues of the single-channel CSMA dynamics persist. For most networks, we expect that a larger number of available channels should alleviate these temporal starvation issues. However, we prove that the aggregate throughput is a non-increasing function of the number of available channels. To investigate this trade-off that emerges between aggregate throughput and temporal starvation phenomena, we propose an analytic framework to study the transient dynamics of multi-channel CSMA networks by means of first hitting times. Our analysis further reveals that the mixing time of the activity process does not always correctly characterize the temporal starvation in the multi-channel scenario and often leads to pessimistic performance estimates.

Collision avoidance in shared slots in wireless devices of the Internet of Things: models and simulations

In this paper, we propose an analysis of a slot-based protocol designed for devices of the Internet of Things (IoT). In contrast to other TDMA-based protocols, this scheme uses a random technique to access shared slots, similarly to CSMA protocols. In practice, the transmissions are scheduled in a given backoff window of slots whose duration allows the transmission of a packet and its acknowledgment. Therefore, this protocol can be analyzed according to the methodology introduced by Bianchi for the IEEE 802.11 protocol even if the protocol studied differs in many aspects. The model we use is also particular because we succeed in obtaining a Markov model even though the scheme used to send a packet (in a node) may depend on the transmission of the previous packet. We distinguish two protocols; in the first one, at the initial stage or after a successful transmission, the packets are transmitted without any backoff, whereas in the second protocol each transmission is always preceded by the count down of a random backoff. Extensive simulations validate both protocols models. In addition, the performances of these protocols are compared with those of slotted Aloha and a protocol using a constant backoff window.

Spatial Mean-Field Limits for Ultra-Dense Random-Access Networks

Random-access algorithms such as the CSMA protocol provide a popular mechanism for distributed medium access control in wireless networks. In saturated-buffer scenarios the joint activity process in such random-access networks has a product-form stationary distribution which provides useful throughput estimates for persistent traffic flows. However, these results do not capture the relevant performance metrics in unsaturated-buffer scenarios, which in particular arise in an IoT context with highly intermittent traffic sources. Mean-field analysis has emerged as a powerful approach to obtain tractable performance estimates in such situations, and is not only mathematically convenient, but also relevant as wireless networks grow larger and denser with the emergence of IoT applications. A crucial requirement for the classical mean-field framework to apply however is that the node population can be partitioned into a finite number of classes of statistically indistinguishable nodes. The latter condition is a severe restriction since nodes typically have different locations and hence experience different interference constraints. Motivated by the above observations, we develop in the present paper a novel mean-field methodology which does not rely on any exchangeability property. Since the spatiotemporal evolution of the network can no longer be described through a finite-dimensional population process, we adopt a measure-valued state description, and prove that the latter converges to a deterministic limit as the network grows large and dense. The limit process is characterized in terms of a system of partial-differential equations, which exhibit a striking local-global-interaction and time scale separation property. Specifically, the queueing dynamics at any given node are only affected by the global network state through a single parsimonious quantity. The latter quantity corresponds to the fraction of time that no activity occurs within the interference range of that particular node in case of a certain static spatial activation measure. Extensive simulation experiments demonstrate that the solution of the partial-differential equations yields remarkably accurate approximations for the queue length distributions and delay metrics, even when the number of nodes is fairly moderate.

CSMA-Based Utility-Optimal Scheduling in the WLAN With a Full-Duplex Access Point

Full-duplex wireless communication has been recognized as an effective technique to improve the system throughput. This paper designs a CSMA-based utility-optimal scheduling scheme to fully explore the performance improvement brought by AP’s full-duplex capability. In particular, to keep the backwards compatibility of the legacy users, we allow users to compete to access the channel using the CSMA protocol in their uplink transmissions while let the AP select its downlink user to communicate with for completing the full-duplex transmission upon each uplink access. Moreover, to achieve the optimal system utility, we then formulate an optimization problem of maximizing the downlink aggregate utility subject to the uplink users’ data rate constraints. The formulated problem falls into a mixed integer nonlinear programming form, which is generally NP-hard to solve. To make the problem tractable, we divide it into user pairing and access-intensity adjustment subproblems. More specifically, we devise a user pairing criterion based on the signal-to-interference-plus-noise ratio to reduce the uplink-downlink interference, and adopt the Hungarian algorithm to find the best matching between uplink and downlink users. After that, we adjust the access-intensity of users (i.e., the ratio of the mean packet transmission time to the mean backoff time) to maximize the downlink aggregate utility based on the geometric programming. Simulation results are presented to evaluate the performance of our scheduling design and demonstrate the downlink aggregate utility improvement compared to other scheduling schemes in full-duplex WLANs.

Hybrid Slotted-CSMA/CA-TDMA for Efficient Massive Registration of IoT Devices

Recently, the Wi-Fi alliance announced a new Wi-Fi standard known as IEEE 802.11ah (or Wi-Fi HaLow) to efficiently support Internet of Things (IoT) applications. However, the existing registration method under IEEE 802.11ah, based on carrier-sense multiple access with collision avoidance (CSMA/CA), was analyzed as not efficient enough for registration of large-scale machine-to-machine (M2M) communications where a massive number of devices try to access a single, centralized access point (AP). In this paper, we propose a hybrid slotted-CSMA/CA–time-division multiple access (TDMA) (HSCT) medium access control (MAC) protocol for efficient massive registration of IoT devices (up to 8000) in M2M networks. We focus on situations, where a large number of M2M devices simultaneously try to register at a single, centralized AP. In the proposed HSCT, contention-based slotted-CSMA/CA allows devices to send an authentication request via randomly selected backoff slots, whereas contention-free TDMA permits those devices to send/receive the subsequent association request/association response via an individually allocated TDMA slot. In addition, a centralized authentication control (CAC)-based mechanism with modified algorithms for optimal selection of CAC parameters and the slotted fixed-window CSMA protocol with Sift geometric probability distribution are used to mitigate severe contention between massive registrations upon network (re-)initialization from an AP reboot. This paper also analyzes the performance of the proposed scheme and determines the optimal configuration to enhance registration performance. Simulation results demonstrate that the proposed HSCT MAC protocol achieves substantial improvement, compared with the contention-free transmission, a combined authentication/association scheme, and the conventional IEEE 802.11ah with CSMA/CA.

NoPSM: A Concurrent MAC Protocol over Low-Data-Rate Low-Power Wireless Channel without PRR-SINR Model

Concurrent MAC protocols can improve channel usage of wireless sensor networks (WSNs), and provide a high-performance infrastructure for data intensive applications. Most of the existing concurrent MAC protocols are based on proactively constructed physical interference models, i.e., PRR-SINR models (PSM). However, it incurs relatively high bandwidth and energy overheads to construct PSM for WSNs. In this paper, we propose NoPSM, which does not take PSM as base to determine transmission concurrency. Instead, the base of NoPSM is reactively constructed interference relationships by passively analyzing overlapping relationships among time logs of block data transmissions and corresponding reception status of each packet in blocks. In this way, NoPSM has two salient features. First, NoPSM is able to construct interference relationships among nodes quickly and accurately along with block data transmissions without needs of network downtime. Second, based on the constructed interference relationships, NoPSM can make decisions of transmission concurrency with a comprehensive criterion, which not only estimates quality of any active links after initiating a new link, but also estimates throughput improvement gained from concurrent transmissions. NoPSM has been implemented in Tinyos-2.1 and extensively evaluated in TOSSIM. Experimental results show that NoPSM improves system throughput by up to 60 percent compared with a traditional CSMA protocol, which cannot exploit potential transmission concurrency. Moreover, NoPSM can gain up to 55 percent throughput improvement as compared to an existing reactive concurrent MAC.

Effective Static and Adaptive Carrier Sensing for Dense Wireless CSMA Networks

The increasingly dense deployments of wireless CSMA networks arising from applications of Internet-of-things call for an improvement to mitigate the interference among simultaneous transmitting wireless devices. For cost efficiency and backward compatibility with legacy transceiver hardware, a simple approach to address interference is by appropriately configuring the carrier sensing thresholds in wireless CSMA protocols, particularly in dense wireless networks. Most prior studies of the configuration of carrier sensing thresholds are based on a simplified conflict graph model, whereas this paper considers a realistic signal-to-interference-and-noise ratio model. We provide a comprehensive study for two effective wireless CSMA protocols: Cumulative-interference-Power Carrier Sensing and Incremental-interference-Power Carrier Sensing, in two aspects: (1) static approach that sets a universal carrier sensing threshold to ensure interference-safe transmissions regardless of network topology, and (2) adaptive approach that adjusts the carrier sensing thresholds dynamically based on the feedback of nearby transmissions. We also provide simulation studies to evaluate the starvation ratio, fairness, and goodput of our approaches.

ANALYSIS OF MULTI-CHANNEL TWO-DIMENSIONAL PROBABILITY CSMA AD HOC NETWORK PROTOCOL BASED THREE-WAY HANDSHAKE MECHANISM

Abstract In wireless Ad Hoc networks, large number and flexible mobility of terminals lead to the rarity of wireless channel resources. Also the hidden and exposed terminal problem exists in the Ad Hoc network which is the major factors restricting its development and applying. Considering these factors, this paper proposes a new CSMA protocol: multi-channel two-dimensional probability CSMA for wireless Ad Hoc network protocol based on three-way handshake mechanism, and analyzes the system throughput, delay of information packet, energy consumption and other properties under the control of the proposed protocol. By using the cycle analysis method, computer simulation results not only verify the theoretical analysis, but also show that the protocol has the optimum performance. The proposed protocol can not only reduce the collision probability of information packets to some extent, improving the channel utilization, reducing the waste of channel resources, but also achieve the balancing of load in a variety of wireless Ad Hoc network services, meeting the needs by different priorities with different QoS, and ensuring the systematic efficiency and fairness.

The One-persistent Multichannel CSMA Protocol with Monitoring Functions Based on Conflict Resolution Algorithm in WSN

In the Wireless Sensor Network, a new MAC protocol: one-persistent CSMA protocol with monitoring functions and multichannel mechanism for Wireless Sensor Network based on conflict resolution algorithm is proposed. Protocol from the system throughput, collision rate, better service quality for higher priority and other aspects improve the traditional CSMA system to perfect the controllability of the system, making the system more stable for the big data, better adapted to different business. The average cycle method is used to derive rigorous mathematical expressions of specific relevant parameters. Using MATLAB simulation tool for the accuracy of the agreement is demonstrated.

Study On The Discrete Time Multichannel Three Dimensional Probability Csma Protocol In Wsn

Abstract With the development of the times, in the wireless sensor networks, the increasing amount of information transmission requires more advanced transmission protocols. Especially accompanied by the arrival of the era of Big Data, the conflicts between traditional transport agreement and the sudden or large amount of data are increasingly prominent. The discrete time three-dimensional probability CSMA protocol with multichannel mechanism proposed solves these problems pretty well. By the new MAC protocol to control transmission of information, so that the agreement adapts various contingencies problems in the network better and has more controllable ability. Using simulation toolMATLAB for the accuracy of the agreement is demonstrated

Analysis Of The Multi-Channel Three Dimensional Probability Csma Protocol With Monitoring Function For Wsn

Abstract For the wireless sensor networks (WSNs), MAC layer protocol, relating to system throughput, involving functions of system, concerning the consumption of system energy efficiency, etc. other system indicators, is very important. With the development of WSN, involving vary businesses, the amount and style of data which the sensor nodes detecting is large and divertive. Based on threedimensional probability CSMA protocol, the proposed protocol, multi-channel three-dimensional probability CSMA protocol with monitoring function (MATP-CSMA), is providing the sensor nodes owning different task with diversified throughput, meeting the quality of services (QoS) of diversiform business. The paper analyses the protocol from three aspects: the system throughput, system delay and energy efficiency. Through rigorous mathematical derivation, get the exact expression of relevant indicators; with the use of simulation tools, verify the accuracy of the model and expressions

Energy Efficiency Analysis of the Discrete Time Three-Dimensional Probability CSMA Protocol in WSN

In the wireless sensor network, energy supply and consumption is the main factors to affect survival time. Introducing the three-dimensional probability CSMA protocol, the paper analyses the system throughput, system delay and energy efficiency with using the average cycle analysis methods. For this protocol, the system time is slotted into a time slot with high channel utilization realized by the choice of three parameters P1, P2 and P3. The correctness of the theory is verified through the simulation.

ADNP-CSMA Random Multiple Access protocol application with the function of monitoring in Ad Hoc network

In Ad Hoc networks,the net work of mobile nodes exchange information with their wireless transceiver equipment,the network throughput is in increased,compared to other such multiple hops network.Moreover along with the rapid development of modern information,communication business also will be increase.However,the access and adaptive of previous CSMA protocol are insufficient.According to these properties,this paper presents a kind of adaptive dual clock with monitoring function P-CSMA random multiple access protocol(ADNP-CSMA),and discusses two kinds of P-CSMA.ACK with monitoring function is introduced to maintain the stability of the whole system,and the introduction of dual clock mechanism reduces the channel of idle period.It calculate the system throughput expression through the method of average period,and the simulation results show that the system is constant in the case of high load throughput.

The Protocol of Probability Detection CSMA with Monitoring Function Based on Isolated Type Two Cross Tree Conflict Decomposition

In the Internet of Things, the CSMA protocol of detection probability of having a monitoring function of isolated binary-based conflict resolution. Analysis methods the averaging period, through rigorous mathematical derivation of accurate mathematical expression protocol-related indicators, and compare with other similar models. Through simulation, simulation and theoretical values consistency, the collision rate is reduced, throughput is significantly improved.