This paper presents a chaos based multi-group CDMA (CCCDMA) scheme employing a modified 1D-Bernoulli map for shared band operation of NB-IoT services with the legacy systems (LTE eNodeB’s). The proposed scheme addresses the capacity requirements for NB-IoT for a very low processing gain and compared with current researches on the topic with relevance to the 3GPP technical report (TR 36.752). Computer simulations reveal a maximum of 120 users can be supported by the CCCDMA scheme for a very low processing gain of N = 31 thereby providing an overloading of ≈ 4 at a reference probability of bit error of 10⁻³ for the IoT scenario. Thus, for a 20 channel system with W = 1 MHz in a 20 MHz band with 4 collaborating user groups, the CCCDMA-IoT scheme provides a Kmax of 2400 IoT UE’s for a 2 dB compromise on SNR.

本文提出了一种基于混沌的多组CDMA（CCCDMA）方案，该方案采用改进的1D-Bernoulli映射与NB-IoT服务与遗留系统（LTE eNodeB）进行共享频带操作。所提出的方案针对非常低的处理增益解决了NB-IoT的容量需求，并与3GPP技术报告（TR 36.752）相关的当前研究进行了比较。计算机仿真显示，CCCDMA方案最多可支持120个用户，以实现非常低的N = 31的处理增益，从而在IoT场景下以10 ^-3的误码参考概率提供≈4的过载。因此，对于在20 MHz频带中W = 1 MHz且具有4个协作用户组的20信道系统，CCCDMA-IoT方案提供了2400 IoT UE的Kmax，以降低SNR 2 dB。