In order to provide voice services with full coverage and high disaster tolerance, satellite communication-based voice solutions utilizing private protocols were proposed, which however cannot be integrated with existing terrestrial voice solutions specified by the 3rd Generation Partnership Project. To overcome this issue, we propose two voice solutions by involving over-thetop (OTT) platform and enhancing Internet protocol multimedia subsystem (IMS), respectively, on the basis of Internet of Things non-terrestrial networks (IoT NTN). The former adopts the advanced hybrid exit linear prediction (AHELP) speech coding and enhanced protocols to adapt to the narrowband and high-latency characteristics of IoT NTN. The latter improves the existing quality of service (QoS) mechanism from the control plane and user plane to achieve an end-to-end QoS guarantee. In addition, a novel Session Initiation Protocol (SIP) signaling adapted to IoT NTN is designed to shorten the calling establishment time, and an NTN voice function is introduced to transform the proposed SIP signaling into typical SIP signaling. A quantitative performance comparison is made between the proposed voice solutions based on OTT and improved IMS through field testing. Finally, some potential trends and challenges for future research are highlighted.

中文翻译：

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用于语音服务的 IoT NTN：架构、协议和挑战


为了提供全覆盖、高容灾的语音服务，提出了基于卫星通信的私有协议语音解决方案，但该解决方案无法与第三代合作伙伴计划指定的现有地面语音解决方案集成。为了克服这个问题，我们提出了两种基于物联网非地面网络（IoT NTN）的语音解决方案，分别涉及OTT平台和增强互联网协议多媒体子系统（IMS）。前者采用先进的混合退出线性预测（AHELP）语音编码和增强协议，以适应物联网NTN的窄带和高延迟特性。后者从控制面和用户面改进现有的服务质量（QoS）机制，实现端到端的QoS保证。此外，设计了一种适用于物联网NTN的新型会话发起协议（SIP）信令，以缩短呼叫建立时间，并引入NTN语音功能，将所提出的SIP信令转换为典型的SIP信令。通过现场测试，对提出的基于 OTT 的语音解决方案和改进的 IMS 的语音解决方案进行了定量性能比较。最后，强调了未来研究的一些潜在趋势和挑战。