Secondary User Power Saving in Overlay Cognitive Radio Networks

Abstract

The secondary user power saving in the overlay based Hybrid Automatic Repeat request cognitive radio has been investigated. The effect of the power splitting ratio on the secondary transmissions has been studied and a simple power saving technique for secondary users is proposed. Extensive simulation runs have been carried out to validate our results.

Secondary User Undercover Cooperative Dynamic Access Protocol for Overlay Cognitive Radio Networks

“…As explained in the introduction, the conventional overlay cognitive radio access forces SUs to split their power and thereby lose transmission opportunities [2]. In contrast, the SUC protocol lets the SU transmit data using full power, while it delegates the interference compensation to other SUs who cooperate to cover the secondary data transmission by relaying the known primary message as shown in Fig.…”

“…3 for the setup in Fig. 2, to obtain prior knowledge about the PU's message [2], which is required to perform the overlay access. In contrast to conventional overlay access, instead of letting each secondary transceiver compensate for its interference by splitting its power and relaying the primary message, we propose a different method in section four that takes into account the compensation process.…”

“…The Overlay access scheme authorizes secondary and primary concurrent access over the same channel; the secondary power is split into two parts, one for the secondary access link and the other part to relay or assist the primary communication [2,3,4,5]. With the correct choice of the power splitting ratio, the potential reduction in a PU's Signal to Interference plus Noise Ratio (SINR) due to the secondary user is exactly compensated by the relaying assistance power.…”

“…In the conventional overlay cognitive radio scheme, described above, SUs must allocate power to compensate the interference caused by their presence so it may arise that the remaining power is not adequate for reliable transmission of secondary data [2]. In such cases, the secondary is forced to keep silent and lose a transmission opportunity.…”