# Two-Tier Cooperation Based High-Reliable and Lightweight Forwarding Strategy in Heterogeneous WBAN  
[PERSON]  
1 School of Information Technology, Henan University of Chinese Medicine, Zhengzhou 450046, China  
to their health and continue to pursue high-quality medical services, how to effectively use the limited energy of sensors to improve the efficiency of WBAN data transmission is still a major challenge faced by researchers. Many studies [3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14] were conducted in an effort to realize energy saving and efficiency improvement for WBAN data transmission by using various methods or technologies, such as developing new energy-saving sensors [3; 4], enhancing the performance of existed data transmission schemes [5; 6; 7], improving channel environment [8; 9; 10] or compressing the amount of data to be transmitted [11; 12; 13; 14]. Usually, most studies adopted one of the above methods to improve the quality of services (QoS) of WBAN. However, it is too ideal because it requires multiple technologies to cooperate simultaneously to efficiently complete WBAN data transmission. It is obvious that the development of new energy-saving sensors and the improvement of the channel environment are usually achieved by improving the technical performance of hardware. From the perspective of improving the performance of soft applications, the combination of new data compression methods and new forwarding models will also effectively improve the efficiency of WBAN data transmission. Compressed sensing technology can compress the original data signal in low dimensional space by using the sparsity of the sampled signal to reduce the amount of data to be transmitted [15], and can also use nonlinear algorithm to finish the precise reconstruction of sparse or compressible signals. Although the literatures [11; 16; 17] have proposed various new compressed sensing methods or models for reducing energy consumption in WBAN, they all have certain limitations because they cannot solve the problem of the inconsistent dimensions of the parameter matrices caused by the heterogeneity of medical data. A semi-tensor product [18] is an extension of traditional matrix multiplication. It not only meets all the characteristics of matrix multiplication, but also can be used when the dimensions of matrix multiplication do not match. STPCS uses a semi-tensor measurement matrix based on compressed sensing. It retains the feature that compressed sensing can compress and encrypt at the same time, and greatly reduces the size of the measurement matrix. [PERSON] et al. [19] have proved that STPCS conforms to Spark, cross-correlation and constrained isometric characteristics, and meets the conditions for accurate signal reconstruction. [PERSON] et al. [20] proposed the compressed sensing of EEG signals to ensure low energy consumption and cheap hardware. The literatures [21; 22; 23; 24] also improved STPCS to reduce the energy consumption of computation and storage while transmitting medical images or data. Obviously, it is feasible and necessary to use STPCS to compress data before transmission. Improving the forwarding performance of medical data after compression can further raise the reliability of data transmission and reduce network energy consumption. Traditional network routing algorithms often chose the path with the least hops between the sink node and source node to transmit data. However, for WBAN, because the energy of each node is very limited, the repeated use of the same path to transmit data information for many times will cause the nodes on this path to consume too much energy, so they will die prematurely. Due to the premature withdrawal of nodes, the original network as a whole has become fragmented and independent of each other, shortening the life cycle of the whole network. Dynamic routing algorithms based on a multi-path mechanism can effectively solve the above problems.