FIELD

The subject matter disclosed herein generally relates to wireless communications and more particularly relates to a method and device for measurement report enhancement for aerial UE.

BACKGROUND

The following abbreviations are defined herewith, at least some of which are referred to in the following description: Third Generation Partnership Project (“3GPP”), Downlink (“DL”), Evolved Node B (“eNB”), Long Term Evolution (“LTE”), Radio Resource Control (“RRC”), Access Network (“AN”), Radio Access Network (“RAN”), User Entity/Equipment (Mobile Terminal) (“UE”), and Uplink (“UL”).

There has been increasing interest in covering aerial vehicles such as drones with cellular networks. The use cases of commercial drones are growing very rapidly and include: package delivery, search-and-rescue, monitoring of critical infrastructure, wildlife conservation, flying cameras, and surveillance. All of these use cases could undergo rapid growth, and more will emerge in coming years. Many of these emerging use cases could benefit from connecting drones to the cellular network as a UE. LTE is well positioned to serve aerial vehicles such as drones. In fact, there have been an increasing number of field-trials involving the use of LTE networks to provide connectivity to drones. It is predicted that a rapid and vast growth in the drone industry will bring new promising business opportunities for LTE operators. To address this growing market demand, a new study item (SI) called “Study on Enhanced LTE Support for Aerial Vehicles” has been approved by 3GPP TSG RAN #75 [1]. The following enhancements were proposed:

Interference mitigation solutions for improving system-level performance in both UL and DL;

Solutions to detect whether a UL signal from an airborne UE increases interference in multiple neighboring cells and whether an airborne UE incurs interference from multiple cells;

Identification of an airborne UE that does not have proper certification for connecting to the cellular network while airborne;

Handover: Identify if enhancements of cell selection and handover efficiency, as well as robustness in handover signaling, can be achieved; and

Positioning: If time allows a 2nd priority, assess the achievable accuracy with existing positioning techniques and identify potential enhancements.

REFERENCES

[1]. RP-170779, “New SID on Enhanced Support for Aerial Vehicles”, NTT DOCOMO INC, Ericsson;

[2]. 3GPP TS 36.331, “Radio Resource Control (RRC) Protocol Specification”;

[3]. R2-1708662, “Potential Enhancements for UAV Interference Problems”, Ericsson;

[4]. R2-1709396, “Measurements Reporting Enhancements for UAV UE, NTT”, DOCOMO INC.;

[5]. R2-1709038, “UL Interference From an Aerial Vehicle”, Intel Corporation;

[6]. R2-1708545, “Measurement Report Mechanism for Drones”, Huawei, HiSilicon; and

[7]. R2-1708973, “Consideration for Interference Detection and Measurement Enhancement for Drone UE”, Lenovo, Motorola Mobility.

The above references are identified by the RAN group from the radio aspect. However, there exist other problematic issues which also need to be solved.

According to the RAN2 #98 online meeting agreement, it was agreed, in the interests of interference detection, to study the enhancement of measurement report mechanisms in order to address the issue of an increased number of strong neighboring cells.

During the RAN2 #99 meeting, several companies proposed solutions for measurement enhancement for the purpose of interference detection, which is summarized as the following:

1). Multi-cell trigger mechanism: when multiple-cell measurement results all fulfill the configured triggering threshold, the measurement report is triggered.

2). Multi-cell trigger mechanism with a timer for max measurement report delay: when multiple cell measurement results all fulfill the configured triggering threshold, the measurement report is triggered. If the measured cells did not fulfill the indicated multi-cell number, then after the timer is expired, the measurement is still triggered to be reported.

3). Specific TTT value: Use aerial specific TTT value with enlarged value compared with terrestrial UEs. And such enlarged TTT value can be used to await more measurement results, so that multiple measurement results can be reported in one measurement report.

However, all of the above mechanisms have disadvantages, for which the key problem may include the following: 1) the multi-cell trigger is not directly related to the total interference that the aerial UE suffers; 2) extra delays are introduced for the measurement report; and/or 3) additional delays will be always introduced, and this is not even considering the total interference from neighboring cells.

BRIEF SUMMARY

Methods and devices for measurement report enhancement for aerial UE are disclosed. A method of measurement report enhancement for aerial UE is disclosed.

In one embodiment, a method of measurement report enhancement, the method comprising: receiving a measurement report configuration with a corresponding threshold and condition configuration and possible new measurement triggering event from eNB; performing measurements of cells according to the new measurement triggering event or new trigger condition; evaluating whether a new triggering condition or the new measurement triggering event is satisfied with the threshold based on the measurement result of cells; and reporting the measurement report to the eNB upon the new triggering condition or new trigger event to be satisfied.

In one embodiment, wherein the measurement report configuration includes: a new measurement event name; a first threshold for determining whether the sum of measurement results of neighboring cells is satisfied; and/or a second threshold for determining whether each neighboring cell result is satisfied, and the number of measured neighboring cells results.

In one embodiment, the new triggering condition includes an (entering) condition 1, the (entering) condition 1 and a (entering) condition 2, or the combination of the (entering) condition 1 and the (entering) condition 2.

In one embodiment, wherein the (entering) condition 1 is that the sum of measurement results of neighboring cells is larger than the first threshold, based on the following formula:
Offset1×10 log(Σi=1m(Offset2i×Pni+Offset3i))+Offset4>ThreshRSRPSum,

Where Pniis the measurement results for ith measured neighboring cell, m is the total number of measured neighboring cells results, or m is the number of cells that fulfill the (entering) condition 2, or m represents the first m measurement results of neighboring cells in the measurement results list, ordered such that the best cell is listed first, and the value of m is configured by the higher layer, ThreshRSRPSum is the threshold for the sum of measurement results of measured neighboring cells, and is expressed in dBm, Offset1is a scaling factor which is configured by eNB for this event, Offset2iis a scaling factor which is configured by eNB for each measured neighboring cell i, Offset3iis an offset value configured by eNB for each measured neighboring cell, and Offset4is an offset value configured by eNB for this event. Pniand Offset3iare expressed in mW in case of RSRP; Offset4and ThreshRSRPSum are expressed in dBm in case of RSRP, or in dB in case of RSRQ and RS-SINR.

In one embodiment, the (entering) condition 2 is that the measurement result of the neighboring cell is better than a threshold based on the following formula:
Mn+Ofn+Ocn−Hys>Thresh

Where the variables in the formula are defined as follows: Mn is the measurement result of the neighboring cell, not taking into account any offsets; Ofn is the frequency specific offset of the frequency of the neighboring cell; Ocn is the cell specific offset of the neighboring cell; Hys is the hysteresis parameter for this event; Thresh is the threshold parameter for this event; Mn and Thresh are expressed in dBm in case of RSRP, or in dB in case of RSRQ and RS-SINR; Ofn, Ocn, Hys are expressed in dB.

A UE for measurement report enhancement, the UE comprising: a transceiver; a processor is configured to control the transceiver to: receiving a measurement report configuration with corresponding threshold and condition configuration and possible new measurement triggering event from eNB; performing measurements of a cells according to the new measurement triggering event or new trigger condition; evaluating whether a new triggering condition for the new measurement triggering event is satisfied with the threshold based on the measurement result of cells; and reporting the measurement report to the eNB when the new triggering condition or new trigger event is satisfied.

