The relationship between RSSI (Received Signal Strength Indication) values and distance is the foundation and the key of ranging and positioning technologies in wireless sensor networks. Log-normal shadowing model (LN...The relationship between RSSI (Received Signal Strength Indication) values and distance is the foundation and the key of ranging and positioning technologies in wireless sensor networks. Log-normal shadowing model (LNSM), as a more general signal propagation model, can better describe the relationship between the RSSI value and distance, but the parameter of variance in LNSM is depended on experiences without self-adaptability. In this paper, it is found that the variance of RSSI value changes along with distance regu- larly by analyzing a large number of experimental data. Based on the result of analysis, we proposed the relationship function of the variance of RSSI and distance, and established the log-normal shadowing model with dynamic variance (LNSM-DV). At the same time, the method of least squares(LS) was selected to es- timate the coefficients in that model, thus LNSM-DV might be adjusted dynamically according to the change of environment and be self-adaptable. The experimental results show that LNSM-DV can further reduce er- ror, and have strong self-adaptability to various environments compared with the LNSM.展开更多
The error will inevitably appear in triangle location in WSNs (wireless sensor networks), and the analysis of its character is very important for a reliable location algorithm. To research the error in triangle locati...The error will inevitably appear in triangle location in WSNs (wireless sensor networks), and the analysis of its character is very important for a reliable location algorithm. To research the error in triangle location algorithm, firstly, a triangle location model is set up;secondly, the condition of the minimal error is got based on the analysis of the location model;at last, by analyzing the condition, the law of error’s changing is ab-stracted, and its correctness is validated by some testing. The conclusions in this paper are all proved, and they provide a powerful foundation and support for reliable location algorithm’s research.展开更多
In WSNs’ applications, not only the reliable end-to-end communications are must be ensured, but also the reduction of energy consumption and the entire network’s lifetim e should be optimized. All of the above have ...In WSNs’ applications, not only the reliable end-to-end communications are must be ensured, but also the reduction of energy consumption and the entire network’s lifetim e should be optimized. All of the above have become to be an important way to evaluate the performance of routing protocols. In this paper, an op-timization model for WSNs’ lifetime is firstly advanced. Secondly, the shortage of ETX based routing metric is solved with the help of the optimization model. Thirdly, an energy balanced routing metric is advanced which is called EBRM in this paper. The result of simulation in NS-2 shows that, the EBRM metric can not only prolong the network’s lifetime, but also can ensure the reliable end-to-end communication.展开更多
文摘The relationship between RSSI (Received Signal Strength Indication) values and distance is the foundation and the key of ranging and positioning technologies in wireless sensor networks. Log-normal shadowing model (LNSM), as a more general signal propagation model, can better describe the relationship between the RSSI value and distance, but the parameter of variance in LNSM is depended on experiences without self-adaptability. In this paper, it is found that the variance of RSSI value changes along with distance regu- larly by analyzing a large number of experimental data. Based on the result of analysis, we proposed the relationship function of the variance of RSSI and distance, and established the log-normal shadowing model with dynamic variance (LNSM-DV). At the same time, the method of least squares(LS) was selected to es- timate the coefficients in that model, thus LNSM-DV might be adjusted dynamically according to the change of environment and be self-adaptable. The experimental results show that LNSM-DV can further reduce er- ror, and have strong self-adaptability to various environments compared with the LNSM.
文摘The error will inevitably appear in triangle location in WSNs (wireless sensor networks), and the analysis of its character is very important for a reliable location algorithm. To research the error in triangle location algorithm, firstly, a triangle location model is set up;secondly, the condition of the minimal error is got based on the analysis of the location model;at last, by analyzing the condition, the law of error’s changing is ab-stracted, and its correctness is validated by some testing. The conclusions in this paper are all proved, and they provide a powerful foundation and support for reliable location algorithm’s research.
文摘In WSNs’ applications, not only the reliable end-to-end communications are must be ensured, but also the reduction of energy consumption and the entire network’s lifetim e should be optimized. All of the above have become to be an important way to evaluate the performance of routing protocols. In this paper, an op-timization model for WSNs’ lifetime is firstly advanced. Secondly, the shortage of ETX based routing metric is solved with the help of the optimization model. Thirdly, an energy balanced routing metric is advanced which is called EBRM in this paper. The result of simulation in NS-2 shows that, the EBRM metric can not only prolong the network’s lifetime, but also can ensure the reliable end-to-end communication.
