Abstract
Internet of Things (IoT) has become an emerging vision for next-generation network and attracts many researchers' attention. In this paper, we propose a novel quasi-synchronous code division multiple access (QS-CDMA) visible light communication (VLC) system for IoT network. A new construction of optical zero correlation zone (OZCZ) code set with orthogonal variable spreading factor (OVSF) is presented for this system, which can meet the multi-rate requirement and tolerate time delay. After deriving the construction and properties of the proposed code set, the maximum numbers of simultaneous users and multiple access interference (MAI) characteristic are analyzed. Furthermore, the signal noise ratio (SNR) and bit error rate (BER) performance of this system are also investigated while taking into account the effects of phase-induced intensity noise (PIIN), shot noise, and thermal noise. The numerical results indicate that the new construction can eliminate MAI and PIIN, which can achieve high quality transmission in the multi-rate QS-CDMA-VLC system for IoT applications.
Highlights
With the rapid development of wireless communication and intelligent user, Internet of Things (IoT) has been emerging as a promising vision for future networks through realizing smart manufacture, smart grid, and smart city [1]–[3]
We investigate the bit error rate (BER) performance of this system adopting orthogonal variable spreading factor (OVSF)-optical zero correlation zone (OZCZ) code set with Psr = −10dBm, Zcz = 1, w = 1, and S = 4
In this paper, a new construction of OVSF-OZCZ code set is proposed for a novel multi-rate quasi-synchronous code division multiple access (QS-code division multiple access (CDMA))-visible light communication (VLC) system model in IoT network, which can significantly enhance the multi-rate transmission performance and reduce the effect of time delay
Summary
With the rapid development of wireless communication and intelligent user, Internet of Things (IoT) has been emerging as a promising vision for future networks through realizing smart manufacture, smart grid, and smart city [1]–[3]. Due to the wide range and diversity of IoT applications, diverse traffic characteristic exhibits in the network, which requires multi-rate wireless communications [10], [11]. D. Chen et al.: New Construction of OVSF-OZCZ Codes in Multi-Rate Quasi-Synchronous CDMA VLC Systems for IoT Applications. To solve the above problems, we present a new construction of OVSF-OZCZ code set to improve the performance of IoT network. A new construction of a unipolar OVSF-OZCZ with zero correlation zone properties and variable spreading factors is first proposed and used in the multi-rate QSCDMA VLC system. The results show that it can effectively support multi-rate communication with more users, and eliminate MAI and PIIN in IoT network.
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