###### Abstract  
With the broadband, noise-like, and non-periodic characteristics of chaotic signals, chaotic digital modulation schemes have received extensive attention. A new short reference orthogonal double bit rate differential chaotic shift keying (SR-ODBR-DCSK) communication scheme is proposed in the paper. The modulation technology generates two orthogonal chaotic signals by using the orthogonality of the chaotic signals acting on the Walsh function and modulates the continuous two-bit data information respectively to achieve the simultaneous transmission of two signals at the same time slot. Odd information bits and even information bits are modulated to two orthogonal signals so as to reach a double transmission rate on the basis of the original channel. In this paper, the performance of SR-ODBR-DCSK in the additive white Gaussian noise (AWGN) channel is analyzed, and a Monte Carlo simulation test is carried out. The bit error rate of this modulation method is compared with that of SR-DCSK. The results show that the SR-ODBR-DCSK system is excellent and promising. differential chaotic shift keying; short reference differential chaotic shift keying; bit transmission rate; bit error rate +
Footnote †: journal: Electronics Letters  
**Clication:** [PERSON]; [PERSON]; [PERSON]. ;  
[PERSON]; [PERSON] Design and Analysis of a Short Reference Orthogonal Double Bit Rate Differential Chaotic Shift Keying Communication Scheme. _Electronics_**2022**, _11_, 2020. [[https://doi.org/10.3390/electronics1132020](https://doi.org/10.3390/electronics1132020)]([https://doi.org/10.3390/electronics1132020](https://doi.org/10.3390/electronics1132020))  
Received: 28 May 2022  
Accepted: 24 June 2022  
Published: 27 June 2022  
**Published:** **Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. increases the complexity of system design. In [16], a novel ambient backscatter communication system is proposed. The short reference DCSK (SR-DCSK) signals are used as radio frequency (RF) sources, and a noise reduction method based on detector averaging operation is designed to improve the bit error rate (BER) performance. [PERSON] proposed a short reference differential chaotic shift keying communication scheme (SR-DCSK) in [17]. The energy efficiency of the system is improved by shortening the reference signal. The transmission rate of the system has not been greatly improved. [PERSON] also proposed an SR-DCSK communication scheme for simultaneous wireless information and power transmission (SWIPT) in [18]. This scheme uses the fact that the reference signal duration of the SR-DCSK scheme is less than half of the transmission signal. Under the premise of keeping the system design simple, it saves energy without sacrificing the incoherent mode of the system and does not reduce the rate of traditional DCSK. DCSK scheme is a suitable candidate for low-complexity spread spectrum communication systems. However, as a transmitted-reference (TR) transmission scheme, its data rate and energy efficiency are limited. DBR-DCSK system can double the data rate but does not improve energy efficiency. SR-DCSK system reduces the energy consumption of transmitting reference signals by shortening the length of the reference time slot, which effectively improves the energy utilization but does not increase the data rate. To enhance the data rate and energy efficiency of the DCSK system, a new SR-ODBR-DCSK scheme is proposed. The main contribution of this paper are summarized as follows:  
Firstly, we propose a new short reference orthogonal double bit rate differential chaotic shift keying communication scheme. In the proposed scheme, the information bits are divided into odd information bits and even information bits, and the reference signal is passed through the quadrature to generate two quadrature signals that can carry odd information bits and even information bits, respectively, to achieve double-speed information transmission, which is twice as fast as SR-DCSK communication scheme.