Resource allocation in mimo multi-cellular networks via submodular optimization
View Patent ↗A method to allocate resources in a wireless MIMO system, by enforcing per-cell orthogonality to avoid intra-cell interference; and allocating resources based on interference handling.
1. A method to allocate resources in a wireless system to optimize communication between a set of sources and a plurality of mobile wireless devices over a plurality of orthogonal resource slots, comprising: enforcing each source to transmit to at-most one device over each orthogonal slot; enforcing the number of data streams transmitted by a source to a device is identical on all slots on which the source transmits to the device; optimizing a metric responsive to the assignment of resource: slots to mobile devices by each source: in the set, said optimizing including approximately maximizing a monotonic sub-modular function under a matroid constraint.
2. The method of claim 1 , comprising allocating resources assuming interference suppression at each scheduled device.
3. The method of claim 2 , wherein each scheduled device suppresses interference from signals intended for co-slot devices served by other sources, with linear filtering.
4. The method of claim 2 , comprising, estimating interference covariance at a scheduled device without explicit signaling about the co-slot interference.
5. The method of claim 2 , comprising determining a feasible assignment of resource slots to devices for a predetermined source.
6. The method of claim 5 , comprising probabilistically updating a current assignment of a source to a good assignment and notifying other sources if the good assignment is taken.
7. The method of claim 6 , comprising checking for convergence.
8. The method of claim 1 , comprising allocating resources assuming interference cancellation by each scheduled device.
9. The method of claim 8 , comprising decoding the codewords intended for other devices.
10. The method of claim 8 , wherein scheduled devices cancel interference from signals intended for co-slot devices served by other sources.
11. The method of claim 8 , comprising imposing scheduling restrictions to minimize signaling overhead.
12. The method of claim 8 , comprising enforcing that each scheduled device sees the same set of co-slot devices served by other sources or any subset of those devices.
13. The method of claim 8 , comprising selecting the best multi-cell allocation element that is feasible under constrained scheduling given a set of selected multi-cell allocation elements and adding the best multi-cell allocation element to the set of selected multi-cell allocation elements.
14. The method of claim 1 , comprising allocating resources under interference avoidance.
15. The method of claim 14 , wherein only one device across all M cells is scheduled on each slot.
16. The method of claim 14 , comprising selecting the best allocation element that is feasible under constrained scheduling given a set of selected allocation elements and adding the best allocation element to the set of selected allocation elements.
17. A method to allocate resources in a wireless system to optimize communication between a set of sources and a plurality of mobile wireless devices over a plurality of orthogonal resource slots, comprising:
enforcing each source to transmit to at-most one device over each orthogonal slot;
enforcing the number of data streams transmitted by a source to a device is identical on all slots on which the source transmits to the device;
optimizing a metric responsive to the assignment of resource slots to mobile devices by each source in the set; and
employing the following optimization problem:
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where ω (q) denotes a choice of device and transmission format at cell q; M denotes the number of cells, N denotes the number of slots, Ω (q) denotes the set of all possible such choices at cell q; r((ω (1) , ω (2) , . . . , ω (M) ),n) is the weighted sum rate obtained for the corresponding M choices of devices and their transmission formats on slot n when interference suppression is employed at each device, χ(ω (q) , n) is an indicator function that returns a value of one if the choice of device and transmission format denoted by ω (q) is selected by cell q on slot n and zero otherwise; u denotes a device; ƒ 1 ,ƒ 2 denote transmission formats.
18. A method to allocate resources in a wireless system to optimize communication between a set of sources and a plurality of mobile wireless devices over a plurality of orthogonal resource slots, comprising:
enforcing each source to transmit to at-most one device over each orthogonal slot;
enforcing the number of data streams transmitted by a source to a device is identical on all slots on which the source transmits to the device;
optimizing a metric responsive to the assignment of resource slots to mobile devices by each source in the set; and
employing the following optimization problem:
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where ω (q) denotes a choke of device and transmission format at cell q; M denotes the number of cells, N denotes the number of slots, Ω (q) denotes the set of all possible such choices at cell q; r((ω (1) , ω (2) , . . . , ω (M) ),n) is the weighted sum rate obtained for the corresponding M choices of devices and their transmission formats on slot n when interference cancellation is employed at each device, χ(ω (q) , n) is an indicator function that returns a value of one if the choice of device and transmission format denoted h ω (q) is selected by cell q on slot n and zero otherwise, u denotes a device; ƒ 1 ,ƒ 2 denote transmission formats.