Spectrum sharing between primary users and coexistence groups of secondary users
Embodiments assign shared spectrum resources to access points. Embodiments group the access points into coexistence groups of access points, and generate a vertex graph including vertices that each represent one of the coexistence groups, where an edge connecting a pair of vertices in the vertex graph represents an overlap between coverage contours of a pair of coexistence groups represented by the pair of vertices, and the edge is assigned a weight that is proportional to the overlap as compared to other overlaps between coverage contours of other pairs of coexistence groups. Embodiments generate at least one vertex-colored graph by assigning a color to each vertex in the vertex graph, group the coexistence groups into groups of coexistence groups based on their corresponding assigned colors in the at least one vertex-colored graph, and map shared spectrum transmit frequencies to the groups of coexistence groups.
1. A method for assigning shared spectrum resources to access points, comprising:
grouping the access points into coexistence groups of access points;
generating a graph including vertices that each represent one of the coexistence groups, wherein a connection in the graph between a pair of the vertices representing a pair of the coexistence groups is assigned a weight based on an amount of interference between the pair of the coexistence groups;
generating at least one graph by assigning at least one of a label or a letter a-to each vertex in the graph;
grouping the coexistence groups into groups of coexistence groups based on at least one of their corresponding assigned label or letter in the at least one graph; and
mapping shared spectrum transmit frequencies to the groups of coexistence groups, wherein each access point in a group of coexistence groups is configured to transmit using a transmit frequency that is assigned to the group of coexistence groups by the mapping.
2. The method of claim 1 , wherein the mapping of the shared spectrum transmit frequencies to the groups of coexistence groups is performed based on an objective function.
3. The method of claim 1 , wherein the assigning of a transmit power level to each access point uses the at least one graph along with an objective function.
4. The method of claim 2 , wherein the objective function has objective parameters including access point bandwidth and coverage areas, wherein the objective function increases as the objective parameters increase.
5. The method of claim 2 , wherein the objective function has cost parameters including interference costs and switching costs, wherein the objective function decreases as the cost parameters increase, wherein the switching cost is indicative of a negative impact of a candidate assignment requiring an access point to change transmit frequency or power, wherein the interference costs depend at least partly on weights assigned to the connections in the at least one graph.
6. The method of claim 2 , wherein the objective function accounts for constraints including minimum access point bandwidth, minimum access point transmit power, incumbent protection, or guard bands between access point frequency assignments.
7. The method of claim 2 , wherein the at least one graph is used along with the objective function to maximize bandwidth and coverage area of the access points while constraining interference to locations in a protected area.
8. The method of claim 2 , wherein the at least one graph is used along with the objective function to maximize bandwidth and coverage area of the access points while constraining interference to an incumbent device.
9. The method of claim 2 , wherein the at least one graph is used along with the objective function to maximize bandwidth and coverage area of the access points without constraining interference to an incumbent device.
10. The method of claim 9 , wherein, after maximizing bandwidth and coverage area of the access points without constraining interference to an incumbent device, access point transmit power levels are adjusted to constrain an aggregate interference to an incumbent device.
11. The method of claim 10 , wherein the access point transmit power levels are adjusted by applying a fairness criterion.
12. The method of claim 11 , wherein the access point transmit power levels are further adjusted by:
after applying the fairness criterion, determining a leftover margin on the aggregate interference to the incumbent device;
allocating the leftover margin to access points.
13. The method of claim 12 , wherein the access point transmit power levels are further adjusted by:
determining Effective Isotropic Radiated Power (EIRP) deficits for each access point based on access point requested transmit power levels and the power determined by applying the fairness criterion; and
applying a level of reverse water filling of power over the access points such that:
(A) the EIRP deficit after the reverse water filling is the same for all access points, and
(B) the resulting aggregate interference increase at the incumbent device after the reverse water filling is less than or equal to the leftover margin.