Generalized Buffer-State-Based Relay Selection in Cooperative Cognitive Radio Networks

Abstract

In this paper, we propose a novel buffer-state-based relaying selection scheme in the context of cooperative cognitive radio networks (CRNs), supporting the primary and secondary networks. In the proposed scheme, both the effects of inter-network interference and fading are successfully suppressed by introducing a flexible link selection algorithm in the secondary network. More specifically, by relying on the broadcast nature of wireless communication channels between a source node and relay nodes in the secondary network, the associated source packet is shared among multiple relay nodes. This allows us to benefit from the additional degree of freedom. Furthermore, we consider the priority for link selection based on the buffer state of each relay node in the secondary network. This contributes to the avoidance of detrimental empty and full buffer states. Moreover, analytical bounds of the outage probability and the average packet delay are derived for the proposed scheme based on the Markov chain model, in order to verify the numerical results. The overhead required for a central coordinator of the secondary network to monitor channel state information and buffer states are also investigated. Our numerical results demonstrate that the proposed scheme achieves better outage and packet-delay performance than the conventional maxratio-based scheme in the buffer-aided CRN. INDEX TERMS Broadcast, buffer-aided relay, cooperative communication, cognitive radio network, Markov chain, outage probability, packet delay.

Buffer‐aided relaying: a survey on relay selection policies

“…Similar to [30], under i.i.d. fading, the BSB relaying scheme in the scenario of a cooperative radio network (CRN), supporting both primary and secondary networks, was proposed in [32]. In this scheme, by presenting a flexible link selection algorithm in the secondary network, the impacts of both fading and inter‐network interference were eliminated.…”

“…The selection consists of the concept of BSB relay selection, to avoid empty/full buffers, and to increase the number of available links by giving priority for the links selected. The proposed scheme attains better system performance in terms of OP and APD, compared with those of the conventional max‐ratio‐based scheme in BA cognitive radio network [32].…”

Effect of controlling maximum-SNR-based relay selection strategy in cooperative wireless communication systems

“…Other research works have included other factors, such as constraint on the resources of the relay node [14][15][16][17][18][19][20][21][22][23][24]. In [14], a relay selection method was proposed to consider the power consumption of each relay node during helping other nodes.…”

Hybrid NOMA/OMA Broadcasting-and-Buffer-State-Based Relay Selection

“…Moreover, in [25][26][27][28][29][30], broadcasting an information packet from a source node to multiple relay nodes was introduced in the context of the aforementioned buffer-aided cooperative communications; this allows relay nodes to share a common information packet, hence increasing the degree of freedom in buffer states. As a result, the source-to-destination (SD) communication delay was kept at the minimum while achieving the high reliability of buffer-aided relay selection.…”

“…Such broadcasting-and buffer-state-based (BBSB) relay selection schemes were developed in the context of decode-and-forward (DF) [25] and amplify-and-forward (AF) relaying scenarios [26]. Furthermore, the cooperative beamforming mode was incorporated into BBSB relay selection in [27], while BBSB relay selection was introduced to physical-layer security [28], NOMA [29], and cognitive radio networks [30]. Note that, the conventional BBSB schemes of [25][26][27][28] does not rely on NOMA.…”