Method of Heterogeneous Network Mobility
Methods for enhanced heterogeneous network mobility are proposed. In a first novel aspect, the cell size of a target cell is considered when determining the TTT value. In one embodiment, pico-specific Time-to-Trigger (TTT) value is configured. When the target cell to be measured is a picocell, pico-specific TTT value is applied. In a second novel aspect, precise mobility state estimation (MSE) is achieved by considering the effect of cell size. In one embodiment, when counting cell changes, a cell change to/from a small cell would be counted to lesser extent than a cell change between large cells. UE uses effective parameters for measurement evaluation, by applying better speed state estimation with speed scaling and by applying parameter differentiation that can be dependent on cell size.
1 . A method, comprising:
performing handover (HO) operations to/from a plurality of cells by a user equipment (UE) in a mobile communication network;
receiving one or more cell specific weighting factors of one or more corresponding neighboring cells, wherein each weighting factor indicates a speed factor;
performing mobility state estimation (MSE) based on the speed of the UE; and
selecting a HO target cell based on the MSE and the weighting factors according to a predefined speed-based selecting rule.
2 . The method of claim 1 , wherein the predefined speed-based selecting rule requires if the MSE indicates a high-speed UE a cell with the weighting factor indicating a high-speed has higher priority, otherwise, a cell with the weighting factor indicating a high-speed has lower priority.
3 . The method of claim 1 , wherein the weighting factors for each cell are obtained from broadcasting or unicasting message.
4 . The method of claim 3 , wherein the weighting factors are broadcasted in system information block (SIB).
5 . The method of claim 1 , wherein the MSE is based on a HO cell counts and the weighting factors, and wherein the UE stores HO cell counts of cell changes to/from the plurality of cells resulting from the handover operations.
6 . The method of claim 1 , wherein the MSE is based on an absolute speed measurement by the UE.
7 . A user equipment (UE), comprising:
a radio frequency (RF) transceiver that transmits and receives wireless signals in a wireless network;
a handover (HO) circuit that performs HO operations to/from a plurality of cells by a user equipment (UE) in a mobile communication network;
a weighting factor circuit that receives one or more cell specific weighting factors of one or more corresponding neighboring cells, wherein each weighting factor indicates a speed factor;
a mobility state estimation (MSE) circuit that performs a MSE based on the speed of the UE; and
a target cell circuit that selects a HO target cell based on the MSE and the weighting factors according to a predefined speed-based selecting rule.
8 . The UE of claim 7 , wherein the predefined speed-based selecting rule requires if the MSE indicates a high-speed UE a cell with the weighting factor indicating a high-speed has higher priority, otherwise, a cell with the weighting factor indicating a high-speed has lower priority.
9 . The UE of claim 7 , wherein the weighting factors for each cell are obtained from broadcasting or unicasting message.
10 . The UE of claim 9 , wherein the weighting factors are broadcasted in system information block (SIB).
11 . The UE of claim 7 , wherein the MSE is based on a HO cell counts and the weighting factors, and wherein the UE stores HO cell counts of cell changes to/from the plurality of cells resulting from the handover operations.
12 . The UE of claim 7 , wherein the MSE is based on an absolute speed measurement by the UE.
13 . A method, comprising:
sending one or more cell specific weighting factors of one or more corresponding neighboring cells by a base station, wherein each weighting factor indicates a speed factor;
receiving mobility state estimation (MSE) from one or more user equipment (UE) indicating the speed of the UE; and
selecting a HO target cell based on the MSE and the weighting factors according to a predefined speed-based selecting rule.
14 . The method of claim 13 , wherein the predefined speed-based selecting rule requires if the MSE indicates a high-speed UE a cell with the weighting factor indicating a high-speed has higher priority, otherwise, a cell with the weighting factor indicating a high-speed has lower priority.
15 . The method of claim 13 , wherein the weighting factors for each cell are transmitted using broadcasting or unicasting message.
16 . The method of claim 13 , wherein the weighting factors are broadcasted in system information block (SIB).
17 . The method of claim 16 , wherein the MSE of each UE is based on a HO cell counts of corresponding UE and weighting factors, and wherein the corresponding UE stores HO cell counts of cell changes to/from the plurality of cells resulting from the handover operations.
18 . The method of claim 13 , wherein the MSE of a UE is based on an absolute speed measurement by a corresponding UE.