Time Division Multiple Access Algorithm Research Articles

Performance Evaluation of Collision Avoidance for Multi-node LoRa Networks based on TDMA and CSMA Algorithm

LoRa can be used as the communication technology for the intelligent monitoring system. However, LoRa is usually used for outdoor communication. The usage of LoRa as indoor communication has many challenges. One of the challenges is that collision happens when using standard LoRa devices with only one channel. The algorithms based on TDMA (Time-division Multiple Access) and CSMA (Carrier-sense Multiple Access) protocols can be used to address this challenge. These two algorithms can be modified by applying the device that is the center of the network (gateway) as a central control and the data transmitter (sensor node) as a passive device. The test was conducted on the Intelligent Laboratory Monitoring System to evaluate this design on a multi-node LoRa network. RSSI testing proves that the distance and building interference affect the signal strength or RSSI of sensor nodes, so the average RSSI value is -73.75 with an RSSI threshold of value -106. The gateway successfully collected each sensor node data with an average success of about 64.953%. The experiment results show the success rate of the CSMA-based algorithm is 10% versus 100% in TDMA-based algorithm; the delay is 4125 ms for CSMA-based and 428.3 ms for TDMA-based. This result means that the CSMA-based algorithm is more complex, takes more time to process the data than the TDMA-based algorithm, has a low success rate, and is more prone to collisions.

Priority Based Time-Division Multiple Access Algorithm for Medium Range Data Communication in Very High Frequency Radios

In this paper, A novel and efficient time division multiple access (TDMA) algorithm for military last-mile data communication is designed. A dynamic slot assignment method coupled with an out-of-band control mechanism is used for the proposed design. In out-of-band, there is a well-defined control segment along with the data segment. So, if a new node specifically a high priority node arrives at the network, it can signal its arrival by a response in the designated mini-slots and can also check the slot in the network, if no idle slots are available. Assigning priority to the nodes would also ensure the delivery of the important messages first. Query messages are broadcasted by the Central node in order to detect new nodes. This reduces nodes working time and also ensures that the nodes don’t interrupt any existing communication. Furthermore, we describe the feasibility and the reliability of this algorithm for military’s last-mile (end user) data communication.

Real-time road traffic awareness model based on optimal multi-channel self-organized time division multiple access algorithm

Real-time road traffic awareness is a challenge in an intelligent transportation system or internet of vehicles. In this paper, we provide a real-time road traffic awareness model for vehicle drivers based on the optimal multi-channel self-organized time division multiple access algorithm. A system based on this model can be implemented in all kinds of road networks including urban and rural roads or highways and cover a large area. The results indicate that this system can identify more than 5000 vehicles within an identification radius of 40km on rural roads or highways and more than 8000 vehicles within an identification radius of 8km on urban roads. Simulation results show that a system based on this model can meet the drivers’ requirement of obtaining road traffic status in real time.

An Adaptive TDMA Slot Assignment Algorithm for Scalable Wireless Mesh Networks

The media access control (MAC) protocol based on fixed slot allocation has low throughput and high delay in high load wireless mesh network. In order to improve the performance of wireless mesh network, we propose a scalable adaptive time division multiple access (TDMA) slot allocation algorithm based on the existing fixed TDMA. The algorithm uses the network structure of clustering and builds a more optimized frame structure, cluster head dynamically allocates time slot according to the packet number of the cluster member sent and the priority level, at the same time taking into account the situation of nodes joining and leaving to improve the scalability of the network The simulation results on OPNET network simulation platform show that the algorithm is superior to fixed TDMA algorithm in both throughput and delay.

Dynamic time division multiple access algorithm for industrial wireless hierarchical sensor networks

Industrial wireless sensor networks adopt a hierarchical structure with large numbers of sensors and routers. Time Division Multiple Access (TDMA) is regarded as an efficient method to reduce the probability of confliction. In the intra-cluster part, the random color selection method is effective in reducing the retry times in an application. In the inter-cluster part, a quick assign algorithm and a dynamic maximum link algorithm are proposed to meet the quick networking or minimum frame size requirements. In the simulation, the dynamic maximum link algorithm produces higher reductions in the frame length than the quick assign algorithm. When the number of routers is 140, the total number of time slots is reduced by 25%. However, the first algorithm needs more control messages, and the average difference in the number of control messages is 3 410. Consequently, the dynamic maximum link algorithm is utilized for adjusting the link schedule to the minimum delay with a relatively high throughput rate, and the quick assign algorithm is utilized for speeding up the networking process.

Many-to-one communication protocol for wireless sensor networks

This paper proposes a novel communication protocol, called Many-to-One Sensors-to-Sink (MOSS), tailored to Wireless Sensor Networks (WSNs). It exploits the unique sensors-to-sink traffic pattern to realise low-overhead medium access and low-latency sensors-to-sink routing paths. In conventional schedule-based Medium Access Control (MAC) protocols such as S-MAC, sensor nodes in the proximity of the event generate reports simultaneously, causing unreliable and unpredictable performance during a brief but critical period of time when an event of interest occurs. MOSS is based on Time Division Multiple Access (TDMA) that avoids energy waste due to collisions, idle listening and overhearing and avoids unreliable behaviour mentioned above. A small test-bed consisting of 12 TelosB motes as well as extensive simulation study based on ns-2 have shown that MOSS reduces the sensor-to-sink latency by as much as 50.5% while consuming only 12.8-19.2% of energy compared to conventional TDMA algorithms.

Self-Stabilizing Deterministic Time Division Multiple Access for Sensor Networks

An algorithm for time division multiple access (TDMA) is found to be applicable in converting existing distributed algorithms into a model that is consistent with sensor networks. Such a TDMA service needs to be self-stabilizing so that in the event of corruption of assigned slots and clock drift, it recovers to states from where TDMA slots are consistent. Previous self-stabilizing solutions for TDMA are either randomized or assume that the topology is known upfront and cannot change. Thus, the question of feasibility of self-stabilizing deterministic TDMA algorithm where the topology is unknown remains open. In this paper, we present a self-stabilizing deterministic algorithm for TDMA in networks where a sensor is only aware of its neighbors. To our knowledge, this is the first such algorithm that achieves these properties. Moreover, this is the first algorithm that demonstrates the feasibility of stabilization-preserving deterministic transformation of a program in shared-memory model on an arbitrary topology into a program that is consistent with the sensor network model.

An optimal topology-transparent scheduling method in multihop packet radio networks

Many transmission scheduling algorithms have been proposed to maximize the spatial reuse and minimize the time-division multiple-access (TDMA) frame length in multihop packet radio networks. Almost all existing algorithms assume exact network topology information and do not adapt to different traffic requirements. Chlamtac and Farago (1994) proposed a topology-transparent algorithm. Following their approach, but with a different design strategy, we propose another algorithm which is optimal in that it maximizes the minimum throughput. We compare our algorithm with that of Chlamtac and Farago's and with the TDMA algorithm, and find that it gives better performance in terms of minimum throughput and minimum and maximum delay times. Our algorithm requires estimated values of the number of nodes and the maximum nodal degree in the network. However, we show that the performance of our algorithm is insensitive to these design parameters.