Expectation from the LTE is to have a increased data rate as compare to previous technologies but at the cell edges LTE suffers from reduced data because of low signal or high interference. To mitigate the risk of low transfer rate at the cell edges LTE relays nodes are used.
LTE relaying is different then a normal repeater. A relay actually receive, demodulates and decodes the data, apply any error correction, etc to it and then re-transmits a new signal. In this way, the signal quality is enhanced with an LTE relay, rather than suffering degradation from a reduced signal to noise ratio when using a repeater.
Relay nodes can optionally support higher layer functionality, for example decode user data from the donor eNB and re-encode the data before transmission to the UE.
Core Advantages of LTE Relay Node
Increase network density
Network coverage extension
Rapid network roll-out
LTE relay operational scenarios:
Half-Duplex: A half-duplex system provides communication in both directions, but not simultaneously.
Full Duplex: For full duplex, the systems are able to transmit and receive at the same time.
Type of Relay
Inband: If the link between the base station and the relay node are on the same carrier frequency as the link between the LTE relay node and the user equipment.
Outband: For Outband LTE relay nodes, RNs, the BS-RN link operates of a different carrier frequency to that of the RN-UE link.