Journal of Systems Engineering and Electronics ›› 2019, Vol. 30 ›› Issue (5): 823-830.doi: 10.21629/JSEE.2019.05.01

• Electronics Technology •     Next Articles

Approach to MAI cancellation for micro-satellite clusters

Jiajun HUANG(), Chaojie ZHANG*(), Xiaojun JIN()   

  • Received:2018-12-19 Online:2019-10-08 Published:2019-10-09
  • Contact: Chaojie ZHANG E-mail:11624025@zju.edu.cn;zhangcj@zju.edu.cn;axemaster@zju.edu.cn
  • About author:HUANG Jiajun was born in 1994. He received his B.E. degree from Dalian Maritime University. He is a Ph.D. candidate of the Micro-Satellite Research Center, Zhejiang University. His research interests include micro-transponder, inter-satellite ranging, and inband full-duplex. E-mail: 11624025@zju.edu.cn|ZHANG Chaojie was born in 1982. He received his B.E. and Ph.D. degrees from Zhejiang University in 2004 and 2009, respectively. Now he is an associate researcher at Zhejiang University. He has joined in the Micro-Satellite Research Center since he was a graduate student. His research interests include micro-satellite and software-defined radio technologies. E-mail: zhangcj@zju.edu.cn|JIN Xiaojun was born in 1977. He received his B.E, M.E. and Ph.D. degrees from Zhejiang University in 2001, 2004 and 2007, respectively. He joined the faculty of Zhejiang University in 2009 and has been an associate professor since 2010. His research interests include micro-satellite transponder technology, relative ranging, and navigation of micro-satellite formation flying. E-mail: axemaster@zju.edu.cn
  • Supported by:
    the China National Funds of Distributed Young Scientists(61525403);the Fundamental Research Funds for the Central Universities(2018QNA4053);This work was supported by the China National Funds of Distributed Young Scientists (61525403) and the Fundamental Research Funds for the Central Universities (2018QNA4053)

Abstract:

With the development of micro-satellite technology, traditional monolithic satellites can be replaced by micro-satellite clusters to achieve high flexibility and dynamic reconfiguration capability. For satellite clusters based on the frequency division-code division multiple access (FD-CDMA) communication system, the inter-satellite ranging precision is usually constrained due to the influence of multi-address interference (MAI). The multi-user detection (MUD) is a solution to MAI, which can be divided into two categories: the linear detector (LD) and the non-linear detector (NLD). The general idea of the LD is aiming to make a better decision during the symbol decision process by using the information of all channels. However, it is not beneficial for the signal phase tracking precision. Instead, the principle of the NLD is to rebuild the interference signal and cancel it from the original one, which can improve the ranging performance at the expense of considerable delays. In order to enable simultaneous ranging and communication and reduce multi-node ranging performance degradation, this paper proposes an NLD scheme based on a delay locked loop (DLL), which simplifies the receiver structure and introduces no delay in the decision process. This scheme utilizes the information obtained from the interference channel to reconstruct the interference signal and then cancels it from the original delayed signal. Therefore, the DLL input signal-to-interference ratio (SIR) of the desired channel can be significantly improved. The experimental results show that with the proposed scheme, the standard deviation of the tracking steady error is decreased from 5.59 cm to 3.97 cm for SIR = 5 dB, and 13.53 cm to 5.77 cm for SIR = -5 dB, respectively.

Key words: micro-satellite, satellite clusters, multi-user detection (MUD), interference cancellation, inter-satellite ranging