FRACTIONAL FREQUENCY REUSE SCHEMES ASSIGNED TO RADIO NODES IN AN LTE NETWORK
First Claim
1. A method of optimizing frequency allocation in a radio access network (RAN) that includes a plurality of RNs each associated with a cell and a SN operatively coupled to the RNs, the method comprising:
- dividing the RNs in the RAN into a plurality of clusters of RNs;
generating a FFR pattern for each cluster;
allocating transmission frequencies to the RNs in each cluster in accordance with the respective FFR pattern that is generated for each cluster;
estimating bit rates of one or more user equipments (UEs) associated with each cell;
performing a scheduling emulation within each cell using the estimated bit rates for the one or more UEs; and
combining the results of the scheduling emulations for each cell to obtain a systemwide performance metric, and if the systemwide performance metric is less than a target threshold, then repeating one or more of the dividing, generating, allocating, estimating, performing, and combining steps, until the systemwide performance metric meets or exceeds the target threshold.
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Accused Products
Abstract
Arrangements disclosed here provide an LTE E-RAN employing a hierarchical architecture with a central controller controlling multiple LTE radio nodes (RNs). The RNs may be clustered within the small cell network. A fractional frequency reuse (“FFR”) scheme is provided that dynamically computes the FFR allocations at individual RNs and configures the corresponding schedulers within each RN to improve cell-edge users'"'"' experience. Once an FFR pattern has been generated and frequencies allocated, UE throughput can be emulated to predict the resulting bit rates for each UE. Using the prediction, a scheduler emulation may be run to predict the behavior of the system. The results of each cell may then be collected to generate the performance of the entire system, which may in turn be used to generate a new or modified FFR pattern, or new or modified clustering. Optimization of the performance results in an optimized FFR pattern.
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Citations
46 Claims
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1. A method of optimizing frequency allocation in a radio access network (RAN) that includes a plurality of RNs each associated with a cell and a SN operatively coupled to the RNs, the method comprising:
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dividing the RNs in the RAN into a plurality of clusters of RNs; generating a FFR pattern for each cluster; allocating transmission frequencies to the RNs in each cluster in accordance with the respective FFR pattern that is generated for each cluster; estimating bit rates of one or more user equipments (UEs) associated with each cell; performing a scheduling emulation within each cell using the estimated bit rates for the one or more UEs; and combining the results of the scheduling emulations for each cell to obtain a systemwide performance metric, and if the systemwide performance metric is less than a target threshold, then repeating one or more of the dividing, generating, allocating, estimating, performing, and combining steps, until the systemwide performance metric meets or exceeds the target threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A RN communicating with a plurality of user equipment (UE) in a radio access network, comprising:
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a processor; a first input for an FFR pattern; a second input for data about communications performance of a plurality of UEs associated with the RN; a scheduler module receiving data from the first and second inputs and configured to provide as output a scheduling of the plurality of UEs, such that the scheduler module is configured to direct a subset of the plurality of UEs corresponding to cell edge users to high reuse bands at least in part based on data from the second input, and further directs a subset of the plurality corresponding to cell center users to low reuse bands. - View Dependent Claims (20)
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21. A method of optimizing transmission resource allocation in a radio access network (RAN) that includes a plurality of radio nodes (RNs) each associated with a cell and a services node operatively coupled to the radio nodes, the method comprising:
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obtaining at least one system-wide performance metric representing operational performance of the RAN; if the system-wide performance metric is less than a target threshold, then adjusting a system-wide FFR pattern used to allocate transmission resources to the RNs until the system-wide performance metric meets or exceeds the target threshold, the system-wide FFR pattern including a plurality of cluster-based FFR patterns each being allocated to a different cluster of RNs, the RNs in the RAN being divided into a plurality of clusters. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A services node controlling a plurality of radio nodes (RNs) in a radio access network (RAN), the plurality of radio nodes communicating with a plurality of user equipment (UE) in the radio access network, comprising:
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a processor; and a performance evaluation module operatively associated with the processor, the performance module having an input for obtaining at least one system-wide performance metric representing operational performance of the RAN, the performance evaluation module being configured such that if the system-wide performance metric is less than a target threshold, then adjusting a system-wide FFR pattern used to allocate transmission resources to the RNs until the system-wide performance metric meets or exceeds the target threshold, the system-wide FFR pattern including a plurality of cluster-based FFR patterns each being allocated to a different cluster of RNs, the RNs in the RAN being divided into a plurality of clusters.
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39. A method for obtaining system performance metrics for a mobile communications system that includes a radio access network (RAN) having a plurality of radio nodes (RNs) each associated with a cell and services node operatively coupled to the RNs, comprising:
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obtaining an FFR pattern for the RAN; receiving from UEs operational in the cells a measurement of signal strength; based at least in part on the FFR pattern and the measurement of signal strength, emulating scheduling functionality performed by the RNs for allocating transmission resources to the UEs; based at least in part on the emulation, determining at least one performance metric for each of the cells in the RAN. - View Dependent Claims (40, 41, 42, 43, 44, 45)
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46. A services node controlling a plurality of radio nodes (RNs) in a radio access network (RAN), the plurality of radio nodes communicating with a plurality of user equipment (UE) in the radio access network, comprising:
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a processor; a UE SINR calculator module operatively associated with the processor for determining, for different levels of interference, an SINR for each of the UEs from (i) a measurement of signal strength received from the UEs and/or (ii) a measurement of signal strength from the UEs measured on uplink reference signals and (iii) an FFR pattern used to allocate transmission frequencies to the RNs; an SINR bit rate mapping module operatively associated with the processor for mapping each of the SINRs to a per-subcarrier bit rate; and a scheduler emulation module operatively associated with the processor for emulating scheduling functionality performed by each of the RNs for allocating transmission resources to the UEs based at least in part on the per-subcarrier bit rates.
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Specification