MIMO with reserved subframes in primary and secondary base stations
Embodiments of the invention provide a method to efficiently enable Network MIMO for use in the downlink direction. An association is established between a primary NodeB in a first cell and a secondary NodeB in an adjacent second cell. A set of downlink transmission resources is reserved for use by both the primary NodeB and the secondary NodeB. A transport block is transmitted from the secondary NodeB simultaneously with the primary NodeB to a user equipment (UE) near the edge of the first cell in response to a schedule provided by the primary NodeB. A time instance of the reserved transmission resources is released by the secondary NodeB when no simultaneous transmission of a transport block is scheduled within a minimum time.
1. A process of spatial multiplexing in a wireless cellular communications network having a primary base station in a first cell, a secondary base station in a second cell adjacent the first cell, a low-latency, high throughput link between the primary base station and the secondary base station, and one user equipment in an edge region between the first cell and second cells, comprising:
A. sending from the primary base station to the secondary base station over the link packets containing media access control layer transport block information for the one user equipment;
B. establishing from the media access control layer transport block information identical reserved resource block spaces in the resource blocks in the primary and secondary base stations and a reservation schedule in the secondary base station for the one user equipment;
C. reserving resource block spaces in the resource blocks in the secondary base station for more than one user equipment including reserving transmission to the one user equipment in one subcarrier frequency at one time and reserving transmission to another user equipment in another subcarrier frequency at the same time;
D. transmitting from the primary base station to the user equipment PHY control channel information for the one user equipment;
E. simultaneously transmitting from the primary and secondary base stations the media access control layer transport block information to the one user equipment;
F. receiving from the one user equipment in the primary and secondary base stations one of an acknowledgement and no acknowledgement; and
G. releasing the reserved resource block spaces in the secondary base station after a certain time if the secondary base station has not received scheduling information from the primary base station.