Systems and methods for network MIMO
View Patent ↗Multiple-Input Multiple-Output (MIMO) systems and methods are provided for enabling network MIMO among base stations (BSs) and a mobile station (MS). A BS configure a network MIMO zone based on an indication of at least one other BS eligible for network MIMO. The network MIMO zone is defined by resources having at least time and frequency dimensions allocated for master transmission under control of the BS, or slave transmission under control of the other BS eligible for network MIMO. The BS can transmit data on the network MIMO zone to the MS. Where there is no data to transmit to the MS, the BS may transmit data on the network MIMO zone to another MS. To configure the network MIMO zone, the BS may look up in a table combinations of the eligible BSs associated with the indication.
1. A mobile station (MS) in a Multiple-Input Multiple-Output (MIMO) system for enabling network MIMO among the MS and a plurality of base stations (BSs), the MS comprising:
at least one transmitting antenna; and
a control system configured to:
determine BSs eligible for network MIMO;
transmit an indication of the BSs eligible for network MIMO to at least one of the BSs eligible for network MIMO; and
receive data on a network MIMO zone from at least one antenna of a BS of the BSs eligible for network MIMO, the network MIMO zone being defined by a resource allocated for master transmission under control of the BS, or slave transmission under control of another BS eligible for network MIMO
2. The MS of claim 1 , wherein the control system is further configured to:
for open loop transmissions:
receive pilot symbols from the BS and the another BS eligible for network MIMO;
measure Carrier to Interference Ratios (C/Is) based on the pilot symbols; and
transmit the C/Is to at least one of the BSs eligible for network MIMO.
3. The MS of claim 1 , wherein the control system is further configured to:
for closed loop transmissions:
receive pilot symbols from the BS and the another BS eligible for network MIMO;
measure C/Is based on the pilot symbols; and
transmit to at least one of: the BSs eligible for network MIMO the C/Is, a precoding matrix index, or a rank indicating streams for receiving data.
4. The MS of claim 1 , wherein the control system is further configured to:
determine whether the MS is ready to receive network MIMO transmission based on at least one of: an absolute C/I threshold; a difference in the C/Is between the BS and the another BS eligible for network MIMO; instantaneous channel conditions; average channel conditions; or the structure of the MS.