Relaying in a communication system

1. A method comprising:

initiating a set up procedure for a communication link between a station of an access system and a relay node, the relay node being capable of wirelessly communicating with at least one communication device within the coverage thereof, wherein the relay node acts as a communication device towards the station and the set up procedure is initiated according to a set up procedure between the station and communication devices accessing the station directly; and

communicating between the relay node and at least one communication device within the coverage area thereof, wherein the relay nodes acts as a station of an access system towards said at least one communication device;

receiving, at the relay node in a first mode, first information based on a protocol for communication between the station and communication devices within the coverage of the station;

synchronising the relay node with the station based on said first information;

setting up the communication link;

switching the relay node to a second mode for enabling the relay node to transmit second information for communications devices within the coverage of the relay node; and

setting a timing advance on the communication link such that communication devices attached to the relay node are in alignment with the station.

2. A method as claimed in claim 1 , further comprising maintaining synchronization of the relay node with the station based on common reference signals transmitted on the communication link after the setup thereof.

3. A method as claimed in claim 1 , further comprising updating of configuration parameters of the relay node based on system information received via the communications link after the set up thereof.

4. A method as claimed in claim 1 , wherein the first mode enables the relay node to receive system information and the second mode enables the relay node to transmit system information.

5. A method as claimed in claim 1 , wherein the step of communicating between the relay node and at least one communication device comprises communication on a physical broadcast channel and primary/secondary synchronization channel between the relay node and the communication device.

6. A method as claimed in claim 1 , further comprising aligning the uplink timing of relay node attached communication devices to the station by truncating at least one symbol in a subframe for communication on the communication link.

7. A method comprising:

initiating a set up procedure for a communication link between a station of an access system and a relay node, the relay node being capable of wirelessly communicating with at least one communication device within the coverage thereof, wherein the relay node is treated as a communication device accessing the station and the set up procedure is initiated according to a set up procedure between the station and communication devices accessing the station directly;

setting up the communication link between the relay node and the station;

transmitting information based on a protocol for communication between the station and communication devices within the coverage of the station;

synchronising with the relay node based on the information; and

determining a timing advance parameter and communicating the parameter to a communication device for use in compensating a delay cause by the relaying.

8. A method as claimed in claim 7 , wherein the information comprises a relay-specific system information message.

9. A method as claimed in claim 7 , further comprising transmitting relay configuration parameters to indicate if at least one of transparent/non-transparent relay, time duplexing or frequency duplexing relay modes, repeater, amplify and forward, decode and forward, self-backhauling relays are supported.

10. An apparatus comprising:

at least one processor; and

at least one memory including computer program code

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:

initiate a set up procedure for a communication link between a station of an access system and at least one communication device wirelessly communicating with a relay node, wherein the relay node acts as a communication device towards the station and the set up procedure is initiated according to a set up procedure between the station and communication devices accessing the station directly;

control communications between the relay node and the at least one communication device within the coverage area thereof, wherein the relay nodes acts as a station of an access system towards said at least one communication device;

switch the relay node between a first mode and a second mode, and wherein the relay node is configured, when in the first mode, to receive first information based on a protocol for communication between the station and communication devices within the coverage of the station and to synchronise with the station based on said first information, and, when in the second mode, to transmit second information for communications devices within the coverage of the relay node; and

maintain synchronization of the relay node with the station based on common reference signals transmitted on the communication link after the setup thereof.

11. An apparatus as claimed in claim 10 , wherein the apparatus is caused to further perform: update configuration parameters of the relay node based on system information received via the communications link after the set up thereof.

12. An apparatus as claimed in claim 10 , wherein the first mode enables the relay node to receive system information and the second mode enables the relay node to transmit system information.

13. An apparatus as claimed in claim 12 , wherein the system information is communicated on mid 6 physical resource blocks on a broadcast control channel.

14. An apparatus as claimed in claim 10 , wherein the apparatus is caused to perform: communicate at least frequency division duplex and time division duplex transmissions on the communication link.

15. An apparatus comprising:

at least one processor; and

at least one memory including computer program code

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:

initiate a set up procedure for a communication link between a station of an access system and a relay node, the relay node being capable of wirelessly communicating with at least one communication device within the coverage thereof, wherein the relay node is treated as a communication device accessing the station and the set up procedure is initiated according to a set up procedure between the station and communication devices accessing the station directly;

set up the communication link between the relay node and the station;

transmit information based on a protocol for communication between the station and communication devices within the coverage of the station; and

synchronise with the relay node based on said information; and

determine a timing advance parameter and communicating the parameter to a communication device for use in compensating delay caused by the relaying.

16. An apparatus as claimed in claim 15 , wherein the apparatus is caused to further perform: transmit updated configuration parameters via the communication link.