Optimization method of non-channel way CSMA-CA (Carrier Sense Multiple Access-Conflict Avoidance) algorithm based on IEEE802.15.4 standard

Abstract

The invention discloses an optimization method of a non-channel way CSMA-CA (Carrier Sense Multiple Access-Conflict Avoidance) algorithm based on IEEE802.15.4 standard. In the method, the setting of a prior transmission right grade is introduced so that node data frames can be sent once to reduce nodes used by channel competition and delay channel waste brought by the competition; the receipt of an ACK response is brought into an algorithm flow and success or failure of sending is judged so that the communication process is more complete; during cancelling channel occupation is cancelled, thenumber of backoff used by non-competition is avoided to bebeing increased, the probability of sending failure easily occurred is reduced, one-to-one useful load transmission rate is improved from themaximum 120kb / s to the maximum 180kb / s, and the useful load transmission rate can also reach over 150kb / s under the condition that multiple nodes simultaneously send requests, thereby greatly enhancing the effective utilization ratio of channels.

Description

technical field [0001] The invention belongs to the field of wireless communication, and relates to an optimization method of a non-slot CSMA-CA algorithm based on the IEEE802.15.4 standard. Background technique [0002] The CSMA-CA (Carrier Sense Multiple Access with Collision Avoidance) algorithm refers to an algorithm protocol that arbitrates the use of radio frequency channels when multiple nodes try to communicate at the same time, and avoids collisions between channels. Under the standard protocol of different application conditions, its algorithm flow will also be different. [0003] IEEE802.15.4 standard CSMA-CA algorithm workflow is divided into two ways: slotted way (slotted) and non-slotted way (unslotted). Such as figure 1 As shown, it is a flowchart of IEEE 802.15.4 standard CSMA-CA algorithm. In actual use, generally only one of them can be determined to be used according to the usage situation. [0004] Slotted mode: a coordinator must send out a beacon fr...

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Problems solved by technology

[0006] However, in a one-to-many wireless monitoring system using radio frequency signal communication, if the traditional IEEE802.15.4 standard non-slot CSMA-CA algorithm is used, when multiple nodes need to send more data packets at the same time, each node All the data is sent randomly in bursts, the probability of collisions and retransmissions increases rapidly, and the effective transmission efficiency of the channel decreases. Since the data packets cannot be sent out in time, the number of nodes that need to send data increases, and the competition becomes more intense and vicious. Circulation, the transmission efficiency is further reduced, and the accumulation of data causes the system to be unresponsive or even paralyzed

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