Optimising LTE uplink scheduling by solving the multidimensional assignment problem

Inter-cell interference mitigation in LTE networks is important to improve the system throughput. Upcoming Cloud Radio Access Networks (C-RANs) allow controlling multiple cells at a single location enabling novel inter-cell coordination algorithms. Coordinated recourse allocation can be used to achieve optimal spectral efficiency through reduced inter-cell interference. In this paper the uplink resource allocation is optimised by deciding which user terminals served by different base stations should transmit on the same resources. A central meta-scheduler situated in the cloud is responsible for the optimisation. The optimisation is performed using heuristic algorithms to solve the underlying multidimensional assignment problem. The complexity is further reduced to a feasible size by only coordinating a subset of base stations. This way the problem can be solved for real world cellular deployments. The performance for different groupings of cooperatively managed base stations is investigated. Results show that coordinating resource assignment of multiple base stations improves the cell spectral efficiency in general and coordinating three sectors at the same site outperforms coordinating three base stations of different sites.

Subjects

Base station grouping

C-RAN

IMT-Advanced

Inter-cell interference coordination

Interference mitigation

Linear assignment problem

LTE

Multidimensional assignment problem

Radio resource management

DDC Class

004: Informatik

380: Handel, Kommunikation, Verkehr

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Optimising LTE uplink scheduling by solving the multidimensional assignment problem