Robust Mobility Measurements and Inter-Cell Coordination in MMwave Small Cell
Inter-cell coordination and beam-aware scanning with end-to-end UE-BS signaling enhancements for robust HO trigger in a beamforming mmWave network is proposed. From the network and the base station perspective, inter-BS control beam coordination is performed, coupled with neighbor-cell information advertisement to facilitate UE-side beam-aware scanning. Inter-BS CB coordination enables a variety of network planning, pre-determined or random, enhanced with UE-reports and dynamic re-coordination to minimize inter-cell interference. From UE perspective, by utilizing the advertised CB information, UE can learn serving cell and neighbor cell CB pattern for beam-aware scanning. Beam-aware scanning enables power saving fast scanning at the UE with beam-aware HO measurement of neighboring and target cells, which reduces HO latency and avoids unnecessary HO.
1 . A method comprising:
receiving control beam (CB) information of a neighbor base station by a serving base station in a beamforming mobile communication network, wherein the control beam information comprises a CB period, CB patterns, and a CB sweeping order for a collection of CBs of the neighbor base station;
determining CB configuration by coordinating with the neighbor base station, wherein each CB is configured with a set of periodically allocated resource blocks and a set of beamforming weights; and
transmitting the CB configuration of the serving base station and the CB information of the neighbor base station to a plurality of user equipments (UEs).
2 . The method of claim 1 , wherein the collection of the CBs create a radiation pattern that covers an entire service area of a cell.
3 . The method of claim 1 , wherein the CB information is with respect to a common reference.
4 . The method of claim 1 , wherein CB transmissions from different cells have non-overlapping CB periods in time domain.
5 . The method of claim 1 , wherein CB transmissions from different cells have overlapping CB periods in time domain and non-overlapping spatial coverage.
6 . The method of claim 1 , wherein the coordinating involves determining a sweeping order of the different CB patterns to reduce spatial interference among the CB transmissions from the different cells.
7 . The method of claim 1 , further comprising:
receiving measurement reports from the plurality of UEs, wherein the measurement reports comprises detectable CB coverage information.
8 . The method of claim 7 , further comprising:
performing re-coordination with the neighbor base station based on the measurement reports.
9 . The method of claim 7 , further comprising:
determining whether to perform inter-cell handover or intra-cell beam switching based on the measurement reports.
10 . A method, comprising:
receiving control beam (CB) information by a user equipment (UE) from a serving base station in a beamforming mobile communication network, wherein the control beam information comprises a CB period, CB patterns, and a CB sweeping order of a collection of CBs of the serving base station and a neighbor base station;
performing beam-aware scanning over all CBs during advertised CB periods;
transmitting a measurement report to the serving base station, wherein the measurement report comprises detectable CB coverage information.
11 . The method of claim 10 , wherein the UE triggers the measurement reporting based on control beam measurements.
12 . The method of claim 10 , wherein the beam-aware scanning involves triggering scanning only during active CB periods as advertised by the base station.
13 . The method of claim 10 , wherein the beam-aware scanning involves monitoring a channel quality of each control beam of each cell.
14 . The method of claim 13 , wherein the UE measures a cell-specific measurement target (CSMT) based on the channel quality of all control beams of each cell.
15 . The method of claim 14 , wherein the CSMT of a cell indicates a maximum channel quality among all control beams of the cell during a CB period.
16 . The method of claim 14 , wherein the CSMT of a cell indicates an average channel quality of a strongest control beam of the cell during a CB period.
17 . The method of claim 13 , wherein the UE obtains location information during the beam-aware scanning and reports to the serving base station.
18 . A user equipment (UE), comprising:
a receiver that receives control beam information by a user equipment from a serving base station in a beamforming mobile communication network, wherein the control beam information comprises a CB period, CB patterns , and a CB sweeping order of a collection of CBs of the serving base station and a neighbor base station;
a measurement module that performs beam-aware scanning over all CBs during advertised CB periods;
a transmitter that transmits a measurement report to the serving base station, wherein the measurement report comprises detectable CB coverage information.
19 . The UE of claim 18 , wherein the UE triggers the measurement reporting based on control beam measurements excluding dedicated beam measurements.
20 . The UE of claim 18 , wherein the beam-aware scanning involves triggering scanning only during active CB periods as advertised by the base station.
21 . The UE of claim 18 , wherein the beam-aware scanning involves monitoring a channel quality of each control beam of each cell.
22 . The UE of claim 18 , wherein the UE measures a cell-specific measurement target (CSMT) based on the channel quality of all control beams of each cell.
23 . The UE of claim 22 , wherein the CSMT of a cell indicates a maximum channel quality among all control beams of the cell during a CB period.
24 . The UE of claim 22 , wherein the CSMT of a cell indicates an average channel quality of a strongest control beam of the cell during a CB period.
25 . The UE of claim 21 , wherein the UE obtains location information during the beam-aware scanning and reports to the serving base station.