Input data value and beam index filtering in LTE and 5G base stations
Methods and systems for Long Term Evolution (LTE) and Fifth Generation (5G) beam index filtering are presented. According to one aspect, a method for beam index filtering comprises receiving a beam index that was estimated based on information received from a User Equipment (UE); storing the received beam index into a queue of length N for storing received beam indexes, N being greater than one; selecting a beam index from the queue according to a filtering algorithm; and using the selected beam index for transmissions to the UE. In one embodiment, a majority vote algorithm is employed to select the beam index that appears most often in the queue. Where there is a tie between two or more beam indexes, the beam index that was most recently added to the queue is selected. The same concepts may be applied to filter input data or parameters other than beam indexes.
1. A method, performed in a base station in a telecommunications network, for beam index filtering, the method comprising:
receiving a beam index for a User Equipment, UE;
storing the received beam index into a queue of length N for storing received beam indexes, N being greater than one;
selecting a beam index from the queue according to a filtering algorithm; and
using the selected beam index for transmissions to the UE.
2. The method of claim 1 wherein storing the received beam index into the queue of length N for storing received beam indexes comprises storing the received beam index into a First-In, First-Out, FIFO, of length N.
3. The method of claim 1 wherein selecting the beam index comprises selecting a beam index that appears most often in the queue.
4. The method of claim 3 wherein selecting the beam index that appears most often in the queue comprises determining that more than one beam index appears most often in the queue and selecting, from those beam indexes that appear most often in the queue, a beam index that was most recently added to the queue.
5. The method of claim 1 wherein each entry within the queue is assigned a corresponding weight and wherein selecting the beam index comprises:
for each entry in the queue, determining a beam index value in that entry, and incrementing a count of a number of times that the beam index value has appeared in the queue during the selection step according to the corresponding weight for that entry; and
after all entries in the queue have been processed, selecting a beam index with a highest count.
6. The method of claim 5 wherein incrementing the count comprises incrementing the count by a value corresponding to a weight assigned to the queue entry currently being processed.
7. The method of claim 5 wherein each queue entry has a same weight.
8. The method of claim 5 wherein at least one queue entry has a different weight than another queue entry.
9. The method of claim 8 wherein a newer queue entry has a higher weight than an older queue entry.
10. The method of claim 5 further comprising modifying the weight assigned to at least one of the entries within the queue.
11. The method of claim 10 wherein modifying the weight assigned to at least one of the entries within the queue comprises dynamically modifying the weight based on channel conditions.
12. The method of claim 11 wherein dynamically modifying the weight based on channel conditions comprises dynamically modifying the weight based on movement of the UE.
13. The method of claim 1 further comprising initializing the queue prior to storing the received beam index into the queue.
14. The method of claim 13 wherein initializing the queue comprises setting each queue entry to an initialization value.
15. The method of claim 14 wherein setting each queue entry to an initialization value comprises setting each queue entry to a value that is not a beam index value and wherein the initialization values are ignored during the selection step.
16. The method of claim 1 wherein N=9.
17. The method of claim 1 further comprising dynamically changing the length N of the queue based on channel conditions.
18. The method of claim 17 wherein dynamically changing the length N of the queue based on channel conditions comprises dynamically changing the length N of the queue based on movement of the UE.
19. The method of claim 1 wherein receiving the beam index comprises receiving the beam index that was reported from the UE.
20. The method of claim 1 wherein receiving the beam index comprises receiving the beam index that was calculated by the base station based on signals received from the UE.
21. A base station configured to communicate with a User Equipment, UE, the base station comprising a radio interface and processing circuitry configured to:
receive a beam index for the UE;
store the received beam index into a queue of length N for storing received beam indexes, N being greater than one;
select a beam index from the queue according to a filtering algorithm; and
use the selected beam index for transmissions to the UE.