College of computer;
Nanjing University of Posts and Telecommunications;
Nanjing 210003;
China;
Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks;
Nanjing 210003;
China;
Key Lab of Broadband Wireless Communication and Sensor Network Technology;
N anjing University of Posts and Telecommunications;
Ministry of Education;
Nanjing 210003;
China;