Association of Network Cells with Location Information
Aspects of the invention provide methods, apparatuses and computer media for providing cell location information in a digital broadcasting system. A mobile terminal uses the cell location information to form a preliminary handover candidate list. A mobile terminal receives reference coordinates for a reference cell, displacement coordinates for a current cell, and displacement coordinates for neighboring cells over a wireless channel. The mobile terminal consequently determines the locations of the current cell and the neighbor cells based on the coordinates. The mobile terminal determines a range distance for the current cell and includes a neighboring cell in a handover candidate list when the neighboring cell is within the range distance, where the range distance is based on an estimated maximum radius of the current cell and optionally on a cell coverage offset. The handover candidate list is further sorted based on distances of the handover candidates from the current cell.
1 . An apparatus comprising:
a memory; and
a processor configured to retrieve instructions from the memory and to perform:
receiving reference coordinates for a reference cell, current displacement coordinates for a current cell, and first neighbor displacement coordinates for a first neighbor cell of a broadcast system over a wireless channel;
determining a current location of the current cell from the reference coordinates and the current displacement coordinates and determining a first location of the first neighbor cell from the reference coordinates and the first neighbor displacement coordinates;
determining a range distance of the current cell; and
when the first neighbor cell is within the range distance, including the first neighbor cell in a cell candidate list.
2 . The apparatus of claim 1 , wherein the processor is further configured to:
determine the range distance based on an estimated maximum radius of the current cell.
3 . The apparatus of claim 2 , further comprising:
an antenna configured to obtain a signal from a broadcast station that is located in the current cell;
a receiver configured to process the signal; and
wherein the processor is further configured to:
determine the estimated maximum radius based on performance characteristics of the receiver and the antenna.
4 . The apparatus of claim 3 , wherein the processor is further configured to:
determine the estimated maximum radius further based on at least one transmission parameter.
5 . The apparatus of claim 4 , wherein the at least one transmission parameter is selected from the group consisting of a transmission power, a modulation type, and a code rate.
6 . The apparatus of claim 1 , wherein the current displacement coordinates include a current relative latitude and a current relative longitude and the first neighbor displacement coordinates include a first neighbor relative latitude and a first neighbor relative longitude.
7 . The apparatus of claim 2 , wherein the processor is further configured to:
determine the range distance further based on a cell coverage offset.
8 . The apparatus of claim 1 , wherein:
the reference coordinates include first reference coordinates for a first reference cell and second reference coordinates for a second reference cell; and
wherein the processor is further configured to:
select, based on received information, the reference coordinates from one of the first reference coordinates and the second reference coordinates.
9 . The apparatus of claim 2 , further comprising:
a receiver configured to process a signal; and
wherein the processor is further configured to:
determine the estimated maximum radius based on a receiver type and on an estimated cell coverage area of the current cell.
10 . The apparatus of claim 1 , wherein the processor is further configured to:
receive second neighbor displacement coordinates for a second neighbor cell;
determine a second location of the second neighbor cell from the reference coordinates and the second neighbor displacement coordinates; and
when the second cell is within the range distance, include the second neighbor cell in the cell candidate list.
11 . The apparatus of claim 1 , wherein the processor is further configured to:
sort the cell candidate list based on distances of candidate cells from the current cell.
12 . A computer-readable medium having computer-executable instructions that when executed perform:
receiving reference coordinates for a reference cell, current displacement coordinates for a current cell, and first neighbor displacement coordinates for a first neighbor cell of a broadcast system;
determining a current location of the current cell from the reference coordinates and the current displacement coordinates and a first location of the first neighbor cell from the reference coordinates and the first neighbor displacement coordinates;
determining a range distance of the current cell; and
when the first neighbor cell is within the range distance, including the first neighbor cell in a cell candidate list.
13 . The computer-readable medium of claim 12 , wherein the instructions further perform:
determining the range distance based on an estimated maximum radius of the current cell.
14 . The computer-readable medium of claim 13 , wherein the instructions further perform:
determining the range distance further based on a cell coverage offset.
15 . The computer-readable medium of claim 12 , wherein the instructions further perform:
selecting the reference coordinates from one of the first reference coordinates and the second reference coordinates, wherein the first reference coordinates are associated with a first reference cell and the second reference coordinates are associated with a second reference cell.
16 . The computer-readable medium of claim 12 , wherein the instructions further perform:
sorting the cell candidate list based on distances of candidate cells from the current cell.
17 . A method comprising:
receiving reference coordinates for a reference cell, current displacement coordinates for a current cell, and first neighbor displacement coordinates for a first neighbor cell of a broadcast system over a wireless channel;
determining a current location of the current cell from the reference coordinates and the current displacement coordinates and a first location of the first neighbor cell from the reference coordinates and the first neighbor displacement coordinates;
determining a range distance of the current cell; and
when the first neighbor cell is within the range distance, including the first neighbor cell in a cell candidate list.
18 . The method of claim 17 , further comprising:
determining the range distance based on an estimated maximum radius of the current cell.
19 . The method of claim 18 , further comprising:
receiving a signal from a broadcast station through a receiver and an antenna; and
determining the estimated maximum radius based on performance characteristics of the receiver and the antenna.
20 . The method of claim 19 , further comprising:
determining the estimated maximum radius further based on at least one transmission parameter.
21 . The method of claim 20 , wherein the at least one transmission parameter is selected from the group consisting of a transmission power, a modulation type, and a code rate.
22 . The method of claim 17 , wherein the current displacement coordinates include a current relative latitude and a current relative longitude and the first neighbor displacement coordinates include a first neighbor relative latitude and a first neighbor relative longitude.
23 . The method of claim 18 , further comprising:
determining the range distance further based on a cell coverage offset.
24 . The method of claim 17 , wherein the reference coordinates include first reference coordinates for a first reference cell and second reference coordinates for a second reference cell, the method further comprising:
selecting the reference coordinates from one of the first reference coordinates and the second reference coordinates.
25 . The method of claim 18 , further comprising:
determining the estimated maximum radius based on a receiver type and on an estimated cell coverage area of the current cell.
26 . The method of claim 17 , further comprising:
receiving second neighbor displacement coordinates for a second neighbor cell;
determining a second location of the second neighbor cell from the reference coordinates and the second neighbor displacement coordinates; and
when the second cell is within the range distance, including the second neighbor cell in the cell candidate list;
27 . The method of claim 17 , further comprising:
sorting the cell candidate list based on distances of candidate cells from the current cell.
28 . An apparatus comprising:
a memory; and
a processor configured to retrieve instructions from the memory and to perform:
sending first reference coordinates for a first reference cell of a broadcast system over a wireless channel, wherein the first reference coordinates include an absolute latitude value and an absolute longitude value of an approximate center of the first reference cell; and
sending displacement coordinates of a first cell of the broadcast system over the wireless channel, wherein the displacement coordinates include a relative latitude value and a relative longitude value with respect to the approximate center of the first reference cell.
29 . The apparatus of claim 28 , wherein the processor is further configured to:
send second reference coordinates for a second reference cell, wherein the second reference coordinates identify an approximate center of the second reference cell; and
send an indicator that indicates a selected reference cell, wherein the selected reference cell is one of the first reference cell and the second reference cell.
30 . A computer-readable medium having computer-executable instructions that when executed perform:
sending first reference coordinates for a first reference cell of a broadcast system over a wireless channel, wherein the first reference coordinates include an absolute latitude value and an absolute longitude value of an approximate center of the first reference cell; and
sending displacement coordinates of a first cell of the broadcast system over the wireless channel, wherein the displacement coordinates include a relative latitude value and a relative longitude value with respect to the approximate center of the first reference cell.
31 . The computer-readable medium of claim 30 , wherein the instructions further perform:
sending second reference coordinates for a second reference cell, wherein the second reference coordinates identify an approximate center of the second reference cell; and
indicating a selected reference cell from the first reference cell and the second reference cell.
32 . A method comprising:
sending first reference coordinates for a first reference cell of a broadcast system over a wireless channel, wherein the first reference coordinates include an absolute latitude value and an absolute longitude value of an approximate center of the first reference cell; and
sending displacement coordinates of a first cell of the broadcast system over the wireless channel, wherein the displacement coordinates include a relative latitude value and a relative longitude value with respect to the approximate center of the first reference cell.
33 . The method of claim 32 further comprising:
sending second reference coordinates for a second reference cell, wherein the second reference coordinates identify an approximate center of the second reference cell; and
indicating a selected reference cell from a first reference cell and a second reference cell.
34 . The apparatus of claim 1 , wherein the cell candidate list comprises a handover candidate list.
35 . The computer-readable medium of claim 12 , wherein the cell candidate list comprises a handover candidate list.
36 . The method of claim 17 , wherein the cell candidate list comprises a handover candidate list.