MULTI-SITE MIMO COOPERATION IN CELLULAR NETWORKS
A method of serving a given data stream to a target mobile terminal, in a cellular communications network that includes a plurality of transmitting sites wherein each transmitting site including at least one antenna, is provided. The method includes designating at least two of the plurality of transmitting sites as cooperating sites; assigning tones to each transmitting site from a sub-band associated with the cooperating sites; dividing the data stream into at least two sub-data streams, each of the sub-data streams for transmission over selected tones; and interlacing tones of the cooperating sites in accordance with a selected one of a time switching and a frequency switching transmit diversity technique. Other techniques for multi-site MIMO cooperation are also provided.
1 - 20 . (canceled)
21 . A method of transmitting a data stream to a mobile terminal in a communications network including a plurality of transmitting sites, comprising:
designating at least two of the plurality of transmitting sites as cooperating sites, each cooperating site comprising at least two antennas;
receiving a precoder report from the mobile terminal for each cooperating site wherein the precoder report is selected from a precoder set and wherein the precoder report for each cooperating site is independent of the precoder report for the other cooperating sites; and
at each cooperating site, transmitting the data stream to the mobile terminal using a beam formed by the cooperating site's antennas.
22 . The method of claim 21 , further comprising at one or more of the cooperating sites, applying a phase adjustment to the transmission.
23 . The method of claim 22 , wherein the phase adjustment is a frequency selective phase adjustment.
24 . The method of claim 21 , wherein the precoder set for each cooperating site is the same as the precoder set for a single site transmission.
25 . The method of claim 21 , further comprising at each cooperating site, transmitting a common pilot signal, wherein the common pilot signal at each cooperating site is orthogonal to the common pilot signal of the other cooperating sites.
26 . The method of claim 25 , wherein the common pilot signal is used by the mobile terminal for selecting a pre-coder for each cooperating site.
27 . The method of claim 21 , further comprising at each cooperating site, transmitting a superposition dedicated pilot.
28 . The method of 27 , wherein the superposition dedicated pilot is used by the mobile terminal for demodulation of the transmitted data stream.
29 . The method of claim 21 , wherein the communications network is a long term evolution network.
30 . A communications system comprising:
a plurality of transmitting sites, at least two of the plurality of the transmitting sites designated as cooperating sites and configured to transmit a data stream to a mobile terminal, each cooperating site comprising at least two antennas and further configured to:
receive a precoder report from the mobile terminal for each cooperating site wherein the precoder report is selected from a precoder set and wherein the precoder report for each cooperating site is independent of the precoder report for the other cooperating sites; and
transmit the data stream to the mobile terminal using a beam formed by the cooperating site's antennas.
31 . The communications system of claim 30 , wherein the precoder set for each cooperating site is the same as the precoder set for single site transmission.
32 . The communications system of claim 30 , wherein one or more of the cooperating sites is further configured to apply a phase adjustment to the transmission.
33 . The communications system of claim 32 , wherein the phase adjustment is a frequency selective phase adjustment.
34 . The communications system of claim 30 , wherein each cooperating site is further configured to transmit a common pilot signal, wherein the common pilot signal at each cooperating site is orthogonal to the common pilot signal of the other cooperating sites.
35 . The communications system of claim 34 , wherein the common pilot signal is used by the mobile terminal for selecting a pre-coder for each cooperating site.
36 . The communications system of claim 30 , wherein each cooperating site is further configured to transmit a superposition dedicated pilot.
37 . The communications system of claim 36 , wherein the superposition dedicated pilot is used by the mobile terminal for demodulation of the transmitted data stream.
38 . The communications system of claim 30 , wherein the communications system is a long term evolution network.