Relay reception synchronization system and method
View Patent ↗A method for informing a relay node when to receive data. The method includes the relay node being informed of a fixed point in a subframe of data when an access node will begin transmitting relevant data over a physical downlink shared channel. The method further includes the relay node beginning to receive data at approximately the fixed point.
1. A method for operating a relay node in a wireless communications network including an access node configured to transmit control information in an access node physical downlink control channel (PDCCH) region, the method comprising:
transmitting, by the relay node, control data to a user equipment (UE) in the network over a relay node PDCCH in a subframe, wherein the relay node is configured to have information on a single fixed point in the subframe for the access node to begin to transmit data to the relay node over an access node physical downlink shared channel (PDSCH) in the subframe; and
beginning, by the relay node, to receive data over the access node PDSCH at or before the single fixed point in the subframe, wherein the single fixed point is the only starting location at or before which the relay node attempts to begin receiving data transmitted from the access node over the access node PDSCH after transmitting control data to the UE over the relay node PDCCH in the subframe, wherein the relay node PDCCH is located in a first Orthogonal Frequency-Division Multiplexing (OFDM) symbol of the subframe and wherein the single fixed point is during a second OFDM symbol of the subframe.
2. The method of claim 1 , further comprising:
receiving, by the relay node, the information on the single fixed point via high layer signaling; and
using, by the relay node, the information on the single fixed point such that the relay node detects data transmitted by the access node without blindly decoding the access node PDSCH of the subframe.
3. The method of claim 2 , wherein the high layer signaling comprises using at least one of:
a broadcast control channel;
radio resource control (RRC) signaling; or
a media access control (MAC) control element.
4. The method of claim 1 , wherein the single fixed point is pre-configured or preset, and wherein the relay node receives no signaling for the information on the single fixed point from the access point.
5. The method of claim 1 , further comprising, receiving, by the relay node, dummy data in at least a portion of the access node PDSCH, wherein the portion is between a point where the access node stops transmitting control information over the access node PDCCH region and begins transmitting actual PDSCH data to the relay node in the access node PDSCH of the subframe.
6. The method of claim 1 , wherein beginning to receive the data comprises beginning to listen for the data at a point in time that is earlier than the single fixed point by an amount of time corresponding to a relay switching delay.
7. The method of claim 1 , wherein the size of the access node PDCCH region comprises one OFDM symbol.
8. The method of claim 1 , wherein the access node is configured to transmit the control information during a first duration in the subframe, and
wherein transmitting, by the relay node, the control data comprises transmitting, by the relay node, the control data during a second duration in the subframe transmitted from the access node, the second duration overlapping at least partially with the first duration.
9. An access node in a wireless telecommunications system, the access node comprising:
a processor configured such that the access node transmits control information in an access node physical downlink control channel (PDCCH) region,
wherein the processor is further configured such that the access node transmits, to a relay node, information on a single fixed point in a subframe for the access node to begin to transmit data to the relay node over an access node physical downlink shared channel (PDSCH) in the subframe, and
wherein the access node is configured to transmit the information on the single fixed point via high layer signaling, wherein the information on the single fixed point instructs the relay node that the single fixed point is the only starting location at or before which the relay node is to begin listening for data transmitted over the access node PDSCH after transmitting control data over a relay node PDCCH in the subframe, wherein the relay node PDCCH is located in a first Orthogonal Frequency-Division Multiplexing (OFDM) symbol of the subframe and wherein the single fixed point is during a second OFDM symbol of the subframe.
10. The access node of claim 9 , wherein the high layer signaling comprises using at least one of:
a broadcast control channel;
radio resource control (RRC) signaling; or
a media access control (MAC) control element.
11. The access node of claim 9 , wherein the size of the access node PDCCH region comprises one OFDM symbol.
12. The access node of claim 11 , wherein, irrespective of the size of the access node PDCCH region, the access node transmits the data to the relay node starting at the second OFDM symbol of the subframe.
13. The access node of claim 9 , wherein the access node is further configured to transmit dummy data to the relay node in at least a portion of the access node PDSCH of the subframe, wherein the portion is between the endpoint of the access node PDCCH region and a point where the access node begins transmitting actual PDSCH data in the access node PDSCH of the subframe.
14. The access node of claim 9 , wherein the access node is further configured to inform the relay node to begin to receive data at a point in time before the single fixed point in order to compensate for delay resulting from the relay node transitioning from a transmission mode to a reception mode.
15. A relay node in a wireless telecommunications system including an access node configured to transmit control information in an access node physical downlink control channel (PDCCH) region, the relay node comprising:
a processor configured such that the relay node transmits control data to a user equipment in the system over a relay node PDCCH in a subframe,
wherein the relay node is configured to have information on a single fixed point in a subframe for the access node to begin to transmit data to the relay node over an access node physical downlink shared channel (PDSCH) in the subframe,
wherein the single fixed point is the only starting location at or before which the relay node attempts to begin receiving data from the access node over the access node PDSCH in the subframe after transmitting control data to the UE over the relay node PDCCH in the subframe, wherein the relay node PDCCH is located in a first Orthogonal Frequency-Division Multiplexing (OFDM) symbol of the subframe and wherein the single fixed point is during a second OFDM symbol of the subframe.
16. The relay node of claim 15 , wherein the relay node is further configured to receive the information on the single fixed point via high layer signaling.
17. The relay node of claim 16 , wherein the high layer signaling comprises using at least one of:
a broadcast control channel;
radio resource control (RRC) signaling; or
a media access control (MAC) control element.
18. The relay node of claim 15 , wherein the single fixed point is pre-configured or preset, and wherein the relay node is configured to receive no signaling for the information on the single fixed point from the access point.
19. The relay node of claim 15 , wherein the relay node is further configured to receive dummy data in at least a portion of the access node PDSCH of the subframe, wherein the portion is between the endpoint of the access node PDCCH region and a point where the access node begins transmitting actual PDSCH data in the access node PDSCH of the subframe.
20. The relay node of claim 15 , wherein the relay node is configured to begin to receive the data transmitted from the access node at a point in time that is earlier than the single fixed point by an amount of time corresponding to a relay switching delay.
21. The relay node of claim 15 , wherein the size of the access node PDCCH region comprises one OFDM symbol.
22. The relay node of claim 15 , wherein the access node is configured to transmit the control information during a first duration, and
wherein the relay node is configured to transmit the control data during a second duration, the second duration overlapping at least partially with the first duration.
23. A method for operating a relay node in a wireless communications network including an access node and user equipment, the method comprising:
receiving, by the relay node, control information from the access node, wherein the control information is received over an access node physical downlink control channel (PDCCH);
transmitting, by the relay node, control data to the user equipment over a relay node PDCCH in a subframe, wherein the relay node is configured to have information on a single fixed point for the access node to begin to transmit data to the relay node over an access node physical downlink shared channel (PDSCH) in the subframe; and
beginning, by the relay node, to receive data over the access node PDSCH at or before the single fixed point in the subframe, wherein the single fixed point is during a second Orthogonal Frequency-Division Multiplexing (OFDM) symbol of the subframe, wherein the second OFDM symbol is the only starting location at or before which the relay node attempts to begin receiving data transmitted over the access node PDSCH after transmitting the control data to the UE over the relay node PDCCH in the subframe.
24. The method of claim 23 , wherein the size of the access node PDCCH comprises one OFDM symbol, and
wherein at least a portion of the second OFDM symbol in the subframe contains dummy PDSCH data that is irrelevant to the relay node, wherein the portion is between a point where the access node stops transmitting information over the access node PDCCH region and begins transmitting actual PDSCH data to the relay node in the access node PDSCH of the subframe.
25. The method of claim 4 , wherein the size of the access node PDCCH region in which the control information is transmitted from the access node is not less than the size of the relay node PDCCH in the subframe transmitted from the relay node.
26. The method of claim 5 , wherein the access node PDCCH region in which the control information is transmitted from the access node is not the same as the relay node PDCCH in the subframe transmitted from the relay node.
27. The relay node of claim 18 , wherein the size of the access node PDCCH region in which the control information is transmitted from the access node is not less than the size of the relay node PDCCH in the subframe transmitted from the relay node.
28. The relay node of claim 19 , wherein the access node PDCCH region in which the control information is transmitted from the access node is not the same as the relay node PDCCH in the subframe transmitted from the relay node.
29. The method of claim 1 , wherein the access node informs the relay node to begin listening for PDSCH data at a point that is beyond the endpoint of the largest possible access node PDCCH region in which the control information is transmitted from the access node.
30. The method of claim 1 , wherein the relay node PDCCH has a fixed endpoint.