Systems and methods for generating a pre-coding code book
In a network comprising a signal forwarding node, a pre-coding code book generating method, wherein the method comprises: generating a pre-coding code book, wherein the pre-coding code book comprises at least one pre-coding code word corresponding to the signal forwarding node, and the pre-coding code word comprises one or more antenna beamforming weights; and communicating the pre-coding code book to a user equipment.
1. A method in a network node for determining a pre-coding code book for multiple antenna transmission, the network node comprised in a network, the network further comprising a signal forwarding node, the method comprising:
generating a pre-coding code book that comprises at least one pre-coding code word associated with the signal forwarding node, the at least one pre-coding code word comprising one or more antenna beam-forming weights; and
communicating the pre-coding code book to a user equipment;
wherein the signal forwarding node is newly added to the network and wherein generating a pre-coding code book that comprises at least one pre-coding code word associated with the signal forwarding node comprises adding the at least one pre-coding code word to a pre-determined pre-coding code book.
2. The method of claim 1 , wherein the signal forwarding node is added after the pre-determined pre-coding code book is determined and the pre-determined pre-coding code book does not include a code word associated with the signal forwarding node.
3. The method of claim 2 , wherein generating the pre-coding code book comprises generating the at least one pre-coding code word associated with the signal forwarding node and including the at least one pre-coding code word in the pre-coding code book.
4. The method of claim 3 , wherein generating the at least one pre-coding code-word further comprises receiving at the network node a reference signal transmitted from the signal forwarding node.
5. The method of claim 4 , wherein generating the at least one pre-coding code word further comprises measuring the reference signal.
6. The method of claim 5 , further comprising determining said one or more antenna beam-forming weights based on measurements of the reference signal.
7. The method of claim 6 , further comprising forming the at least one pre-coding code word to comprise the determined one or more antenna beam-forming weights and including said pre-coding code word in the pre-coding code book.
8. The method of claim 7 , further comprising transmitting to the signal forwarding node a trigger message that causes the signal forwarding node to transmit the reference signal.
9. The method of claim 2 , further comprising transmitting a reference signal to the signal forwarding node.
10. The method of claim 9 , further comprising receiving said one or more antenna beam-forming weights from the signal forwarding node and adding the at least one pre-coding code word, comprising the received one or more antenna beam-forming weights, to the pre-coding code book.
11. The method of claim 10 , wherein receiving the one or more antenna beam-forming weights comprises receiving the at least one pre-coding code word from the signal forwarding node, the at least one pre-coding code word comprising the one or more antenna beam-forming weights.
12. The method of claim 2 , wherein said generating step is performed periodically.
13. The method of claim 12 , wherein said generating step is performed periodically at an interval set by the network node.
14. The method of claim 2 , wherein said generating step is performed only during any one of a system initialization period and a new user set-up procedure.
15. The method of claim 2 , wherein said communicating comprises communicating a pre-coding code book size to the user equipment using a common control channel and using candidate pre-coding vectors as weights of common reference signals.
16. The method of claim 2 , further comprising optimizing the pre-coding code book using any one of a dirty-paper coding algorithm and sub-optimal pre-coding algorithm.
17. The method of claim 2 , wherein:
generating the pre-coding code book comprises updating a pre-coding code book,
the network node comprises a base station, and
the signal forwarding node comprises a repeater or relay.
18. A base station, comprising:
a processor and a memory, said memory containing instructions executable by the processor whereby the base station is configured to:
generate a pre-coding code book that comprises at least one pre-coding code word associated with a signal forwarding node, the at least one pre-coding code word comprising one or more antenna beam-forming weights, wherein the signal forwarding node is newly added to the network and wherein generating a pre-coding code book that comprises at least one pre-coding code word associated with the signal forwarding node comprises adding the at least one pre-coding code word to a pre-determined pre-coding code book; and
communicate the pre-coding code book from the base station to a mobile station.
19. The base station of claim 18 , wherein the signal forwarding node is added after the pre-determined pre-coding code book is determined and the pre-determined pre-coding code book does not include a code word associated with the signal forwarding node.