Multi-Radio Cooperative ARQ in wireless cellular networks: a MAC layer perspective

Multi-Radio Cooperative Automatic Retransmission Request (MC-ARQ) schemes are introduced in this paper within the context of hybrid networks combining long-range and short-range communications. Since the number of wireless devices is incessantly increasing, it is frequently possible to establish a spontaneous cooperative cluster in the close proximity of any wireless device. These devices forming the cluster are connected to both a cellular-based network such as WiMAX, 3G, or LTE and a short-range network based on technologies such as WLAN, Zigbee, Bluetooh, or UWB, among other possibilities. The main idea behind the proposed MC-ARQ scheme is that, upon transmission error through the cellular interface, retransmission can be requested from the wireless grid surrounding the destination device using the short-range interface instead of the primary cellular link. Therefore, besides the cooperative diversity attained with C-ARQ schemes, the traffic load in the cellular interface is reduced benefiting thus a high number of users and reducing both energy consumption and interference. The Persistent Relay Carrier Sensing Medium Access (PRCSMA) protocol is presented as an example of solution for the MAC layer in this emerging new topic.