The number of computations that the relay needs to perform is also limited.
The relay needs to design a contract to maximize its expected revenue.
(1) Additional signaling is needed, e.g., the relay needs to inform eNodeB of its data detection result.
In addition, WPR avoids redundant messages by selecting a subset of one-hop neighbors, the AMPR (Adapted MultiPoint Relay), needed to reach all two-hop ones.
After receiving all sources confirmations, the relay needs to choose one source who can make the relay to maximize its revenue.
Note that in the relay beamforming design problem, each relay needs to determine simultaneously several complex numbers to update its beamforming vectors.
In the relay power control algorithm, each relay needs to determine only a positive real number for its transmit power value.
This is related to the fact that we are using a TDD system and therefore the relay needs to synchronise, store, and forward the received signal.
Similar to transmit power and distance, in order to guarantee the end-to-end channel capacity, the allocation time of each relay needs to be optimized.
