Maximum throughput of a secondary user cooperating with an energy-aware primary user

Abstract

This paper proposes a cooperation protocol between a secondary user (SU) and a primary user (PU) which dedicates a free frequency subband for the SU if cooperation results in energy saving. Time is slotted and users are equipped with buffers. Under the proposed protocol, the PU releases portion of its bandwidth for secondary transmission. Moreover, it assigns a portion of the time slot duration for the SU to relay primary packets and achieve a higher successful packet reception probability at the primary receiver. We assume that the PU has three states: idle, forward, and retransmission states. At each of these states, the SU accesses the channel with adaptive transmission parameters. The PU cooperates with the SU if and only if the achievable average number of transmitted primary packets per joule is higher than the number of transmitted packets per joule when it operates alone. The numerical results show the beneficial gains of the proposed cooperative cognitive protocol.

Spatial–Temporal Queuing Theoretic Modeling of Opportunistic Multihop Wireless Networks With and Without Cooperation

“…In [22] the authors consider uplink of a Time Division Multiple Access (TDMA)-based primary network where some cognitive nodes assist the primary network by re-transmitting some primary packets that were not received successfully at the base-station. In [23] and [24] the authors consider cooperation between a primary user and a relaying secondary user such that the secondary rate is maximized subject to stability of the primary queue. Under the proposed protocol in [23] the primary queueing delay with cooperation is less than that without cooperation and average energy emitted by the secondary user is below a certain threshold.…”

“…Under the proposed protocol in [23] the primary queueing delay with cooperation is less than that without cooperation and average energy emitted by the secondary user is below a certain threshold. Under the proposed protocol in [24] the primary user cooperates with secondary user if and only if the average number of transmitted primary packets per unit energy is higher with cooperation than without. In [25] the authors find optimal cooperative power allocations in a network of multiple secondary users and a single primary user.…”