Cognitive radio ad hoc network (CRAHN) has been considered an efficiently spectrum-aware communication paradigm in wireless networks because of its intrinsic properties of cognition and self-organization. In practice, because primary and secondary ad hoc networks are usually associated with two different types of wireless networks, the synchronization between primary users and secondary users is hardly guaranteed. The multi-channel asynchronous CRAHNs referred to as multi-channel non-time-slotted CRAHNs impose many challenging problems that severely degrade system performance. In this article, we review these challenging issues in multi-channel non-time-slotted CRAHNs, including reactivation- failure, frequently unexpected hand-offs, nonreal- time spectrum aggregation, inefficient power allocation, and frequent re-routing problems. Then, we develop a full-duplex based framework to resolve these issues. Future research directions are discussed to improve system performance of multi-channel non-time-slotted CRAHNs.

中文翻译：

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用于多通道认知无线电自组织网络的全双工


认知无线电自组织网络（CRAHN）因其认知和自组织的内在特性而被认为是无线网络中有效的频谱感知通信范例。在实践中，由于主自组织网络和次自组织网络通常与两种不同类型的无线网络相关联，因此很难保证主用户和次用户之间的同步。多通道异步CRAHN（称为多通道非时隙CRAHN）带来了许多具有挑战性的问题，严重降低了系统性能。在本文中，我们回顾了多通道非时隙 CRAHN 中的这些具有挑战性的问题，包括重新激活失败、频繁的意外切换、非实时频谱聚合、低效的功率分配和频繁的重新路由问题。然后，我们开发了一个基于全双工的框架来解决这些问题。讨论了未来的研究方向，以提高多通道非时隙 CRAHN 的系统性能。