Minimising signal interference within a wireless network
OwnerStephen Hill, Dickson Poon +1inventors
InventorsStephen Hill, Dickson Poon, David Parsons
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Abstract
A wireless telecommunications network (100) comprises a multiplicity of Bluetooth™ units, some of which are fixed and act as base units (BS1; BS2; BS3; BS4) and some mobile (MS1; MS2; MS3; MS4). The fixed units are connected to a Local Area Network (LAN) along with a telephony gateway (4) and a PABX (5) and PSTN (6). Methods for minimising signal interference as mobile units roam within the network are discussed.
Claims16
A method for minimising signal interference within a wireless network comprising a plurality of fixed terminals in wireless communication with one or more mobile terminals roaming within the network, communication links between the fixed and mobile terminals, the method including the steps of generating an integer linear programming problem of the form:
- 10 Min ∑ j ∈ L ( M p j - ∑ i ∈ B a i j x i j ) ( 1 )
- such that:
- 11 ∑ i ∈ B x i j = 1 , j ∈ L ( 2 ) ∑ j ∈ L x i j ≤ q i , i ∈ B ( 3 ) x i j ≤ z i j ( 4 ) ∑ i ∈ B z i j ≤ I level + p j , j ∈ L ( 5 ) p j ≤ I threshold , j ∈ L ( 6 )
- where
- 12 L = the set of mobile terminals B = the set of fixed terminals z i j = { 1 , if the signal of fixed terminal i is received by mobile j 0 , else x i j = { 1 , if fixed terminal i connects with mobile j 0 , else q i = the capacity of fixed terminal i a i j = expected signal quality if mobile terminal j connects with fixed terminal i I level = preferred maximum number of signals from fixed terminals overlapping any mobile terminal location I threshold = maximum extra number of extra fixed terminal signals allowed above I level , that can overlap a mobile terminal location before service is inoperable p j = a non - negative penalty variable
- solving the above relaxed problem (1) to (3);
- determining if the solution satisfies constraints (4) to (6), and, if the solution does satisfy these constraints, using the solution to determine the communication links between the fixed and mobile terminals.
A wireless network located within a network environment and comprising a plurality of fixed terminals in communication with one or more mobile terminals roaming within the network, the network including control means operable to solve an integer linear programming problem of the form:
- 13 Min ∑ j ∈ L ( M p j - ∑ i ∈ B a i j x i j ) ( 1 )
- such that:
- 14 ∑ i ∈ B x i j = 1 , j ∈ L ( 2 ) ∑ j ∈ L x i j ≤ q i , i ∈ B ( 3 ) x i j ≤ z i j ( 4 ) ∑ i ∈ B z i j ≤ I level + p j , j ∈ L ( 5 ) p j ≤ I threshold , j ∈ L ( 6 )
- where
- 15 L = the set of mobile terminals B = the set of fixed terminals z i j = { 1 , if the signal of fixed terminal i is received by mobile j 0 , else x i j = { 1 , if fixed terminal i connects with mobile j 0 , else q i = the capacity of fixed terminal i a i j = expected signal quality if mobile terminal j connects with fixed terminal i I level = preferred maximum number of signals from fixed terminals overlapping any mobile terminal location I threshold = maximum extra number of extra fixed terminal signals allowed above I level , that can overlap a mobile terminal location before service is inoperable p j = a non - negative penalty variable
- by solving the above relaxed problem (1) to (3);
- and to determine if the solution satisfies constraints (4) to (6), and, if the solution does satisfy these constraints, using the solution to determine the communication links between the fixed and mobile terminals.
A network as claimed in claim 10, wherein the control means is operable to solve the relaxed problem by:
- creating a first bipartite graph with the set of fixed and mobile terminals;
- applying weightings to the edges of the first bipartite graph to create a weighted bipartite graph;
- and
- solving an optimal assignment problem for the weighted bipartite graph to derive a second graph having a second set of edges, to determine a new set of connections between mobile and fixed terminals.
Dependencies are inferred from the claim text.