Cooperative diversity (CD) is a physical hardware arrangement technique that uses multiple antennas to improve a network’s total channel capacity for any set of bandwidths. In traditional “single hop” antenna systems, a receiver obtains a direct signal from a source and sends the information to that antenna’s end user. Other signals are also received which may need to be re-directed to the appropriate antenna, called “relay signals,” but in a single hop system, these relay signals are ignored. This can cause bandwidth bottlenecks if the relay signals are not being properly directed to their appropriate antenna.
In a cooperative diversity network where there are multiple antennae available, each antenna considers both direct and relayed signals as relevant information. The direct signals are processed as normal and the relayed signals are re-directed to their appropriate antenna for end processing. This allows a network to receive many different signals at once as opposed to only a few at a time. Any relayed signal received that isn’t at its appropriate antenna will be spider-webbed across the network until it reaches the correct antenna, allowing for more information to be sent. This technique also works with antennae controlled by many different users (called cooperative user diversity).