Research On Cooperative Communication Transmission Strategy In Wireless Body Area Network

Wireless body area networks(WBAN)have been widely used in medical health,sports and military activities.However,in the implementation and application of WBAN,due to the complex human communication environment,the RF signal will suffer obvious energy attenuation when it is transmitted in the human area.In addition,the resource of biosensor is very limited due to its size,and it is usually not feasible to charge and replace the device in the human environment.Therefore,how to improve the reliability of data transmission and energy consumption is a crucial issue in WBAN.The research shows that cooperative communication is the key technology to improve the performance of wireless communication network.This technology can improve the reliability and energy efficiency of data transmission by deploying relay nodes in WBAN.Therefore,this paper studies the cooperative communication transmission strategy in WBAN.First of all,in order to solve the problem that fixed slot allocation can not adapt to the channel conditions dynamically,which leads to low energy utilization of nodes,this paper proposes a cooperative communication transmission strategy based on dynamic slot allocation.This strategy uses Markov model to model the wireless channel.According to the real-time channel state information and the node data rate requirements,the transmission time slot is dynamically adjusted.According to the direct transmission and relay transmission,the expression of data transmission interruption probability is derived.The simulation results show that compared with the existing cooperative transmission strategy,the proposed strategy can meet the change of node rate,effectively reduce the interruption probability of data transmission under the changeable channel conditions,thus providing higher reliability and energy efficiency.Then,aiming at the problem that the nature of data collection is not considered in WBAN cooperative communication,which leads to redundant data transmission and reduces network life,this paper proposes a cooperative communication transmission strategy based on key data.This strategy uses mutual information standard to classify the data sensed by sensor nodes,and only when the mutual information value is less than the predetermined threshold,data transmission is allowed.In addition,the strategy transmits key data through relay cooperation,and derives the mathematical model of quality of service(Qo S)index and related subjective functions to ensure data transmission.The simulation results show that compared with the existing cooperative transmission strategy,the proposed strategy can prevent redundant data transmission according to the nature of the collected data,save the residual energy of the nodes while meeting the reliability of data transmission,thus extending the network life.Finally,on the basis of the above research,this paper further studies the incremental cooperative communication with different number of relays in WBAN,and proposes an incremental cooperative communication transmission strategy based on multiple relays.The strategy uses incremental cooperation to transmit data.It judges whether to use relay according to the short feedback information of the destination node data transmission,and only uses relay to cooperate when the direct transmission fails.In addition,for the case of three candidate relays,the analytical expressions of energy efficiency and packet error rate of data transmission are studied,and the network performance is evaluated from three aspects: network lifetime,no de residual energy and packet loss rate.Simulation results show that compared with the existing cooperative transmission strategy,the proposed strategy effectively reduces the retransmission of sensor data,enhances the reliability of the network and provides better performance.