SHARP: Spectrum Harvesting with ARQ Retransmission and Probing in Cognitive Radio

Abstract

Abstract-In underlay cognitive radio, a secondary user transmits in the transmission band of a primary user without serious degradation in the performance of the primary user. This paper proposes a method of underlay cognitive radio where the secondary pair listens to the primary ARQ feedback to glean information about the primary channel. The secondary transmitter may also probe the channel by transmitting a packet and listening to the primary ARQ, thus getting additional information about the relative strength of the cross channel and primary channel. The method is entitled Spectrum Harvesting with ARQ Retransmission and Probing (SHARP). The probing is done only infrequently to minimize its impact on the primary throughput. Two varieties of spectrum sharing, named conservative and aggressive SHARP, are introduced. Both methods avoid introducing any outage in the primary; their difference is that conservative SHARP leaves the primary operations altogether unaffected, while aggressive SHARP may occasionally force the primary to use two instead of one transmission cycle for a packet, in order to harvest a better throughput for the secondary. The performance of the proposed system is analyzed and it is shown that the secondary throughput can be significantly improved via the proposed approach, possibly with a small loss of the primary throughput during the transmission as well as probing period.

Delay and Throughput Analysis of Cognitive Go-Back-N HARQ in the Face of Imperfect Sensing

“…In the context of ARQ aided CR systems, there are only a limited number of references [79], [80], [93]- [103], which are illustrated in Timeline 2. However, none these references have provided the detailed theoretical throughput and delay analysis of ARQ-assisted CR systems.…”

“…However, none these references have provided the detailed theoretical throughput and delay analysis of ARQ-assisted CR systems. Specifically, in [93]- [95], it is assumed that the CUs infer the activity of the PUs via observing their feedbacks flags. Touati et al [96] have performed the seminal performance analysis of ARQ-aided and relay-assisted CR systems.…”

Opportunistic Spectrum Sharing in Cognitive Radio Networks

“…If PU is an error control system or rate adaptive system, PR sends the primary Automatic Repeat-reQuest (ARQ) signals [36][37][38][39][40] or quantized feedback of h pp to PT [41], respectively. SU may estimate the spectrum opportunities by eavesdropping the primary feedback, as shown in Fig.…”

Opportunistic Spectrum Sharing With Limited Feedback in Poisson Cognitive Radio Networks

“…This motivated recent research on spectrum sharing with limited channel feedback [3]- [9]. SUs may obtain primary channel information via PU cooperation [3], sending probing message [4], eavesdropping primary ARQ (Automatic Repeat-reQuest) messages [5], [6] and overhearing primary quantized feedback [7]- [9]. The above work considered point-to-point or centralized network with the positions of all network nodes fixed.…”