Time division multiple access/frequency division multiple access (TDMA/FDMA)-based wireless sensor network (WSN) medium access control (mac) layer scheduling method

Abstract

The invention discloses a time division multiple access / frequency division multiple access (TDMA / FDMA)-based wireless sensor network (WSN) medium access control (mac) layer scheduling method. By the scheduling method, channels are distributed by using a time division multiplex (TDM) system in clusters and a frequency division multiplex (FDM) system among the clusters aiming at a clustering-based data collection type WSN network. The TDM system and the FDM system favorably overcome the defect of a large number of access conflicts of a contention type mac scheduling method under the condition of high network load. Meanwhile, by the novel mac scheduling method, carrier sense multiple access (csma) time slots are introduced at a communication stage in the clusters, so that the defect of low expansibility of the TDMA scheduling methods is overcome. A node revives in an active period to forward data and enters a dormancy state in an inactive period, so that the energy consumption is lowered. According to the conditions of the network load, by the scheduling method, the duty ratio of the active period in the communication cycle can be automatically adjusted, the dynamic requirements of the network on throughput can be met, and the time delay of the data is reduced to a certain extent.

Description

technical field [0001] The invention belongs to the field of wireless sensor networks (wireless sensor networks, WSN), and in particular relates to a TDMA / FDMA multiplexing-based wireless sensor network mac (medium access control medium access control) layer scheduling method. Background technique [0002] Mac is at the bottom of the wireless sensor network, determines the way nodes access wireless channels, and is responsible for the allocation of wireless channels in the network. The data generated by the upper-layer scheduling method of the network needs to be sent, and how the physical layer realizes the data reception must be realized through the scheduling mechanism of the mac layer. The Mac layer has a direct impact on the performance of the network. The scheduling method of the Mac layer directly affects the throughput of the network, the real-time performance of data, the scalability of the network, and energy consumption. For specific applications, designing a goo...

AI Technical Summary

Problems solved by technology

Compared with the single-channel scheduling method, MMSN improves the throughput of the network, but the complexity of the scheduling method is high. The Toggle Snooping / Toggle Transmission method proposed by MMSN requires frequent switching of new arrivals, which is not feasible. and requires high-precision synchronization

And because MMSN is a competitive scheduling method, when the node density of the network is high and the channels that can be allocated are not enough, or when the data flow in the network increases, the network congestion will increase, and the packet loss rate and delay will increase accordingly. increase

[0007] 2. MC-LMAC is a scheduling method for TDMA / FDMA multiplexing, and the scheduling method also requires high-precision synchronization; due to the use of the TDMA mechanism, the scheduling method has scalability problems

MC-LMAC broadcasts control frames at the beginning of each slot, which introduces a very large control consumption

The scheduling method also has the problem of node sending conflicts. Two nodes may want to send data to one node at the same time, which is similar to the hidden terminal problem.

[0008] 3. The difference between TMCP and other scheduling methods is that it does not require high-precision synchronization, or even synchronization, which is the bottleneck and difficulty of many other scheduling methods

But when the amount of data is small, the network performs well

[0009] Although the above scheduling methods have proposed various methods for multi-channel allocation, there are some shortcomings. The Mac scheduling method either requires high-precision synchronization, or requires complex channel and time slot allocation methods and network initialization processes. The scheduling method has various shortcomings such as high complexity, poor scalability, and high energy consumption.

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