Enabling coordinated multi-point reception
This invention measures the propagation delay τ 1 between the user equipment and a first cooperating unit and the propagation delay τ 2 between the user equipment and a second cooperating unit. These propagation delays are used to compute a timing advance amount to the user equipment to enable coordinated multi-point reception. In a first embodiment one cooperating unit receives a function of the propagation delay, computes the timing advance amount and transmits a timing advance command to the user equipment. In a second embodiment a central unit performs these operations.
1. A method of operating at least two cooperating base station units and a user equipment for coordinated multi-point reception comprising the steps of:
measuring at the first cooperating unit the propagation delay τ 1 between the user equipment and a first cooperating unit;
measuring at the second cooperating unit the propagation delay τ 2 between the user equipment and a second cooperating unit;
computing at the second cooperating unit a function f(τ 2 ) of the propagation delay τ 2 ;
transmitting the value of said computed function f(τ 2 ) from the second cooperating unit to the first cooperating unit;
computing at the first cooperating unit a function g(f(τ 2 ),τ 1 ) of the function f(τ 2 ) and the propagation delay τ 1 ;
computing at the first cooperating unit a timing advance amount for the user equipment for coordinated multi-point reception from the computed function g(f(τ 2 ),τ 1 );
transmitting a timing advance command having the computed timing advance amount from the first cooperating unit to the user equipment; and
operating the user equipment according to the timing advance command.
2. The method of claim 1 , wherein:
said function f(τ 2 ) is a quantization of the propagation delay τ 2 .
3. The method of claim 1 , wherein:
said function f(τ 2 ) is a suggested timing advance amount corresponding to the propagation delay τ 2 .
4. A method of operating at least two cooperating units for coordinated multi-point reception with comprising the steps of:
measuring at a first cooperating base station the propagation delay τ 2 between a user equipment and the first cooperating unit;
measuring at a second cooperating base station the propagation delay τ 2 between the user equipment and a second cooperating unit;
computing at the first cooperating unit a function f(τ 2 ) of the propagation delay τ 1 ;
computing at the second cooperating unit a function f(τ 2 ) of the propagation delay τ 2 ;
transmitting the computed function f(τ 2 ) from the first cooperating unit to a central unit;
transmitting the computed function f(τ 2 ) from the second cooperating unit to the central unit;
computing at a central unit a timing advance amount for the user equipment for coordinated multi-point reception from said functions f(τ 2 ) and f(τ 2 ); and
transmitting a timing advance command having the computed timing advance amount from the central unit to the user equipment.
5. The method of claim 4 , wherein:
said function f(τ 2 ) is a quantization of the propagation delay τ 2 .
6. The method of claim 4 , wherein:
said function f(τ 2 ) is a suggested timing advance amount corresponding to the propagation delay τ 2 .
7. The method of claim 4 , wherein:
said function f(τ 2 ) is a quantization of the propagation delay τ 2 .
8. The method of claim 4 , wherein:
said function f(τ 2 ) is a suggested timing advance amount corresponding to the propagation delay τ 2 .
9. The method of claim 4 , further comprising the step of:
operating the user equipment according to the timing advance command.