Voice Capacity of Cognitive Radio Networks for Both Centralized and Distributed Channel Access Control

Abstract

As an emerging networking technology, cognitive radio networks (CRNs) have drawn immense attention in the wireless networking community. Since multimedia services have become widely popular among wireless communication services users, supporting those services over CRNs has become an interesting research topic in recent years. However, due to the random nature of the resource availability in CRNs, providing quality-of-service (QoS) guarantees for multimedia services is a challenging task. In this paper, we consider a secondary system operating over a time-slotted primary system and secondary users accessing the channels at the spectrum holes without interfering with primary users. As the capacity analysis is one of the basic steps to guarantee QoS, we analyze the constantrate voice capacity of multi-channel fully-connected CRNs under different generic channel access schemes with centralized and distributed control, respectively. The capacity is represented in terms of the number of simultaneous independent voice calls that the secondary system can support, providing stochastic delay guarantee. It is shown that the analytical results closely match with the simulation results, and the number of voice packets that can be simultaneously transmitted in a time-slot per channel has a significant impact on the capacity of the system. With proper medium access control, capacity analysis can help to develop a call admission control policy for QoS provisioning in CRNs.

Secondary VoIP Capacity in Opportunistic Spectrum Access Networks with Friendly Scheduling

“…It is also assumed that the secondary basestation and users are within the full coverage range of the primary network basestation. In this case the secondary basestation can have a highly reliable spectrum sensing capability, and error free spectrum sensing is assumed [13] [14].…”

“…Secondary transmission is accomplished by carrier-sensing at the start of each time slot for a short time period that is sufficiently long to detect if the slot is occupied. A single time-invariant channel model is assumed where the stations use power control [13] [14] and where the packet size is fixed for both primary and secondary traffic flows. It is assumed that each primary packet can be serviced in one time slot.…”

Statistical QoS Evaluation for Cognitive Radio Networks

“…In [4], a single channel cognitive radio network has been analyzed, while in [5], a multi-channel network has been investigated. However, the analysis in [4] and [5] assumes a time-slotted network access. Generally, achieving time synchronization among all nodes in an infrastructureless network is a challenging task.…”

“…In [4] and [5], the maximum number of voice users with QoS guarantees has been analyzed. In [4], a single channel cognitive radio network has been analyzed, while in [5], a multi-channel network has been investigated. However, the analysis in [4] and [5] assumes a time-slotted network access.…”

Link-Layer Resource Allocation for Voice Users in Cognitive Radio Networks

“…In order to guarantee a certain level of qualityof-service (QoS) for delay sensitive applications such as voice service, as any other telecommunication system, a CRN has to be able to avoid saturating the available channels and to allocate resources for each user according to its service requirements [5]. The saturation of a channel is avoided by employing what is called connection admission control [6], while appropriate resource allocation is known as service differentiation. Furthermore, QoS has different parameters depending on the application, such as delay, jitter, packet loss, signal to interference plus noise ratio (SINR), and bit error rate (BER) [7].…”