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Ad Hoc网络的全双工

认知无线电自组织网络（CRAHN）由于其固有的认知和自组织特性，已被认为是无线网络中一种有效的频谱感知通信范例。实际上，由于主要和次要自组织网络通常与两种不同类型的无线网络相关联，因此很难保证主要用户和次要用户之间的同步。被称为多通道非时隙CRAHN的多通道异步CRAHN带来了许多具有挑战性的问题，这些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中的挑战性问题，包括重新激活失败，频繁的意外切换，非实时频谱聚合，低效的功率分配以及频繁的重新路由问题。然后，我们开发了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。