## 1 Introduction  
The wireless sensor network (WSN) is a network information system integrating distributed information acquisition, information transmission and information processing technologies [1; 2; 3; 4]. It adopts a self-organizing method to configure a large number of sensor nodes and collects and processes the target information in the network coverage area through the collaborative work of the nodes. Different from traditional wireless network to improve service quality and efficient bandwidth utilization, this paper adds coding and decoding technology to WSNs, which can greatly improve the anti-noise performance and improve communication quality of WSNs. Low power consumption is especially important for WSN nodes during the design process. Since the energy consumption of the WSN nodes is mainly concentrated in the computing module and the communication module, in addition to adopting dynamic energy management measures for them, the innovation of this paper is to add a non-binary LDPC-CPM coding and decoding module in the traditional WSNs node communication module. In order to improve the data error correction performance of data transmission between sensor nodes and between nodes and aggregation nodes, the WSNs data transmission reliability and WSNs anti-interference performance are enhanced. Highly reliable data transmission can reduce the communication traffic sent and received by the communication module, the reby reducing the energy consumption of the communication module. In this paper, the design of the non-binary LDPC-CPM scheme in WSNs mainly includes the selection of linear block code, coding algorithm, check matrix construction algorithm, decoding algorithm, modulation and demodulation mode and so on. In error correction coding, non-binary LDPC codes are the best ones currently used for error correction capability, low coding complexity and high decoding efficiency and are very suitable for use in WSN [5; 6; 7; 8]. The research shows that the non-binary LDPC code using the belief propagation (BP) algorithm has excellent performance approaching the Shannon limit. LDPC code description is simple, with greatly flexibility and lower error leveling characteristics. Parallel operation, high throughput and high-speed decoding potential have been considered as a class of channel coding schemes comparable to Turbo codes [9; 10; 11; 12]. The low complexity means that the power consumption is lower for practical working systems and thus it is very suitable for hardware implementation on WSN nodes [13; 14; 15]. The non-binary LDPC code can effectively reduce the transmit power received by the sensor node, the reby reducing the energy consumption of a single node. Therefore, the error correction coding scheme introduced in the WSN uses a non-binary LDPC code for a series of coding and decoding processes. The WSNs node is a low-power, low-price micro-embedded device. Its energy supply and wireless communication bandwidth are very limited and the calculation and storage requirements are very high, so the requirements for the type of operation are also high. Therefore, the coding algorithm and check matrix construction algorithm in the non-binary LDPC-CPM scheme proposed in this paper are improved to reduce the computational complexity. In the non-binary LDPC encoding algorithm, the encoding algorithm based on Gauss elimination [16] and efficient encoding algorithm based on the approximate triangular structure (also called greedy algorithm) are suitable for the general check matrix but the check matrix needs to be pretreated in encoding process. The two algorithms all contain the inverse of the matrix. The process of calculating the inverse is not only a large amount of computation, hard to realize the hardware but also full rank of the matrix. In the actual application process, the above conditions cannot be met. In 2004, [PERSON] proposed an iterative encoding algorithm based on binary LDPC codes [17]. This algorithm has linear coding complexity and does not change the sparseness of the matrix.