DATA TRANSMISSION

TECHNOLOGY [0001] Embodiments of the present disclosure generally relate to mobile communication, and more particularly, to a method and device for virtual anchor point based data transmission.

BACKGROUND [0002] Traffic demands in mobile networks are expected to grow substantially in the next years, both in terms of total traffic volume and of high transmission rate required by individual users. To meet the above demands, it is generally agreed that one of the possible solutions is to deploy very dense and heterogeneous wireless networks, also called ultra-dense network (UDN). [0003] FIG. 1 shows a schematic diagram of the UDN. As depicted in FIG. 1, the UDN includes a small cell base station (SeNB), a macro cell base station (MeNB), a service gateway (S-GW) connected to SeNB and MeNB over Sl-U interface, and a mobility management entity (MME) connected to SeNB and MeNB over a Sl-MME interface. [0004] However, in UDNs, with increased mobility of user equipment (UE) (e.g. a mobile device), more frequent handover among cells (or base stations) for a user may become more frequent. On one hand, frequent handover may cause a bad experience of service (EoS). On the other hand, it may also cause more signaling overhead related to mobility management (especially on the backhaul network) and would even make the network collapse. Existing network protocols have been designed to operate efficiently only for the current network density levels and may easily turn into a performance bottleneck when the level of network density keeps increaseing (e.g. UDN), e.g. too frequent mobility management messages are exchanged unnecessarily.

[0005] Therefore, a new mobility management mechanism is expected to be designed for the deployment of UDN. SUMMARY

[0006] In order to overcome the above and other potential problems, a method and device for virtual anchor point based data transmission is provided, which can reduce the signaling overhead caused by frequent handover of a UE among cells (or base stations).

[0007] In first aspect of present disclosure, a method of virtual anchor point based data transmission is provided. The method comprises: establishing a virtual anchor point for a plurality of cells; and transmitting data from the virtual anchor point to the UE located in one of the plurality of cells to reduce overhead of cell handover. [0008] In some embodiments, transmitting data via a virtual anchor point to the UE located in one of the plurality of cells comprises: transmitting the data to the UE by establishing a link between the virtual anchor point and a corresponding cell among the plurality of cells in which the UE is located.

[0009] In some embodiments, transmitting the data to the UE by establishing a link between the virtual anchor point and the corresponding cell among the plurality of cells in which the UE is located comprises: in response to the UE entering a first cell of the plurality of cells from outside of the plurality of cells, transmitting the data to the virtual anchor point via a fixed data path; establishing a first data tunnel between the virtual anchor point and the first cell; transmitting the data from the virtual anchor point to the first cell via the first data tunnel; and transmitting the data from the first cell to the UE.

[0010] In some embodiments, the fixed data path is configured as a reusable data path.

[0011] In some embodiments, the packet head of the data packet transmitted via the first data tunnel includes a first address and a second address.

[0012] In some embodiments, the first address includes a media access control (MAC) address of the virtual anchor point.

[0013] In some embodiments, the second address includes a MAC address of the first cell. [0014] In some embodiments, transmitting the data from the virtual anchor point to the UE located in one of the plurality of cells further comprises: in response to the UE moving from the first cell to a second cell of the plurality of cells, establishing a second data tunnel between the virtual anchor point and the second cell; transmitting the data from the virtual anchor point to the second cell via the second data tunnel; and transmitting the data from the second cell to the UE.

[0015] In some embodiments, the virtual anchor point is configured to include a logic item in a base station located inside the plurality of cells.

[0016] In some embodiments, the virtual anchor point is configured to include a logic item in a base station located outside the plurality of cells. [0017] In some embodiments, the method further comprises: enabling and/or disabling the function of the virtual anchor point with signaling issued from a mobility management entity.

[0018] In some embodiments, the method further comprises: before changing from the virtual anchor point to a new virtual anchor point, receiving a changing request from the virtual anchor point; and in response to receiving the changing request, establishing the new virtual anchor point.

[0019] In second aspect of present disclosure, a device for virtual anchor point based data transmission is provided. The device comprises: a virtual anchor point establishing unit configured for establishing a virtual anchor point for the plurality of cells; and a data transmission unit configured for transmitting data via the virtual anchor point to user equipment (UE) located in one of the plurality of cells to reduce an overhead of a cell handover.

[0020] In some embodiments, the transmission unit comprises: a link establishing unit configured for transmitting the data to the UE by establishing a link between the virtual anchor point and a corresponding cell among the plurality of cells in which the UE is located.

[0021] In some embodiments, the link establishing unit comprises: a first detecting unit configured for detecting the UE entering a first cell of the plurality of cells from outside the plurality of cells; and a first link establishing unit configured for in response to detecting the UE entering a first cell of the plurality of cells from outside of the plurality of cells: transmitting the data to the virtual anchor point via a fixed data path; establishing a first data tunnel between the virtual anchor point and the first cell; transmitting the data via the first data tunnel from the virtual anchor point to the first cell; and transmitting the data from the first cell to the UE.

[0022] In some embodiments, the fixed data path is configured as a reusable data path.

[0023] In some embodiments, the packet head of the data packet transmitted via the first data tunnel includes a first address and a second address.

[0024] In some embodiments, the first address includes a media access control (MAC) address of the virtual anchor point. [0025] In some embodiments, the second address includes a MAC address of the first cell.

[0026] In some embodiments, the link establishing unit further comprises: a second detecting unit for detecting the UE moving from the first cell to the second cell among the plurality of cells; and a second link establishing unit configured for in response to detecting the UE moving from the first cell to the second cell among the plurality of cells: establishing a second data tunnel between the virtual anchor point and the second cell; transmitting the data from the virtual anchor point to the second cell via the second data tunnel; and transmitting the data from the second cell to the UE.

[0027] In some embodiments, the virtual anchor point is configured to include a logic item in a base station located inside the plurality of cells.

[0028] In some embodiments, the virtual anchor point is configured to include a logic item in a base station located outside the plurality of cells.

[0029] In some embodiments, the device further comprises: an activating unit for enabling and/or disabling the function of the virtual anchor point with signaling issued from a mobility management entity.

[0030] In some embodiments, the device further comprises: an anchor point changing unit configured for before changing from the virtual anchor point to a new virtual anchor point, receiving a changing request from the virtual anchor point; and in response to receiving the changing request, establishing the new virtual anchor point. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 illustrates a schematic diagram of a densely deployed network.

[0032] FIG. 2 illustrates a schematic diagram of the virtual anchor point according to embodiments of the present disclosure for use in the densely deployed network of FIG.1.

[0033] FIG. 3 illustrates a flow chart of a method for virtual anchor point based data transmission according to embodiments of the present disclosure.

[0034] FIG. 4 illustrates a signal flow chart during a procedure of the method for virtual anchor point based data transmission according to the embodiments of the present disclosure.

[0035] FIG. 5 illustrates a packet head of a data packet transmitted in a data tunnel according to the embodiments of the present disclosure.

[0036] FIG. 6 illustrates a block diagram of the device for virtual anchor point based data transmission according to the embodiments of the present disclosure.

DETAILED DESCRIPTION OF EMBODIEMTNS

[0037] Principles of the present disclosure will now be described with reference to various example embodiments illustrated in the drawings. Though optional embodiments of the present disclosure are illustrated in the drawings, it is to be understood that the embodiments are described only to facilitate those skilled in the art in better understanding and thereby achieving the present disclosure, rather than to limit the scope of the disclosure in any manner.

[0038] FIG. 2 illustrates a schematic diagram of the virtual anchor point according to embodiments of the present disclosure for use in the densely deployed network of FIG. changing 1.

[0039] As shown in FIG. 2 and referring to FIG. 1, a virtual anchor point is introduced between SGW and a plurality of cells. Thus, SGW and MME are firstly connected to the virtual anchor point via SI-U and SI-MME interfaces and then connected to the base station of each individual cell by the virtual anchor point. Accordingly, data from SGW is also firstly transmitted to the virtual anchor point and then to the UE in the corresponding target cell. As shown in FIGS. 1 and 2, a virtual anchor point usually corresponds to multiple cells which together form the so-called virtual cell (as shown in FIG. 1). It is to be noted that FIG. 1 is only an example figure, and the concept of virtual anchor point is not limited to small cells but can also be applied to cells with larger or smaller coverage.

[0040] FIG. 3 illustrates a flowchart of a method 300 for virtual anchor point based data transmission. In accordance with embodiments of the present disclosure, the method 300 reduces the signaling overhead caused by frequent handover of a UE among cells. With reference to FIG. 1 and FIG. 2 and as illustrated by FIG. 3, the method in general includes following steps. At step 310, a virtual anchor point for a plurality of cells is established. At step 320, data is transmitted to the UE located in one of the plurality of cells via the virtual anchor point to reduce overhead of cell handover. [0041] In some embodiments, the data transmission to the UE via the virtual anchor point further includes transmitting the data to the UE by establishing a link between the virtual anchor point and the corresponding cell among the plurality of cells in which the UE is located.

[0042] FIG. 4 illustrates a signal flow map of the method 300 for virtual anchor point based data transmission according to embodiments of the present disclosure. According to the embodiment as illustrated in FIG. 4, after a virtual anchor point is established (i.e. step 310), the data transmission to the UE via the virtual anchor point (i.e. step 320) may include the following actions.

[0043] In response to the UE entering a first cell of the plurality of cells from outside the plurality of cells (i.e. action 1), at action 2, data is transmitted to the virtual anchor point over a fixed data path. At action 3, a first data tunnel is established between the virtual anchor point and the first cell and the data is transmitted from the virtual anchor point to the first cell via the first data tunnel. At action 4, the data is transmitted from the first cell to the UE. [0044] Optionally, the fixed data path between the virtual anchor point and SGW can be kept, and thus forms a reusable data path. That is, when UE migrates (or is handed over) between different cells, it is unnecessary to establish a new data path, which can significantly reduce the unnecessary overhead owing to the frequent handover.

[0045] Optionally, first data tunnel between the virtual anchor point and the first cell is a data tunnel of General Packet Radio Service (GPRS) tunnel protocol (hereinafter also called GTP tunnel). The data tunnel is an enhanced bi-directional tunnel. To establish an enhanced bi-directional GTP tunnel between SGW and the target cell, only one new packet head for the enhanced data packet is added.

[0046] FIG. 5 illustrates a packet head of a data packet transmitted in a data tunnel according to the embodiments of the present disclosure. As shown in FIG. 5(a), the packet head of the data packet transmitted in the first data tunnel (namely, before handover) includes an Media Access Control (MAC) address of the virtual anchor point and an MAC address of the first cell. As shown in FIG. 5 (b), the packet head of the data packet transmitted in the second data tunnel (namely, after handover, illustrated afterwards) includes an MAC address of the virtual anchor point and the MAC address of the second cell.

[0047] Now continuing to refer to FIG. 4, the data transmission to the UE via the virtual anchor point (i.e. step 320) may further include the following actions. In response to the UE moving from the first cell to the second cell of the plurality of cells (i.e. action 5), at action 6, a second data tunnel is established between the virtual anchor point and the second cell and the data is transmitted from the virtual anchor point to the second cell via the second data tunnel. At action 7, the data is transmitted from the second cell to the UE.

[0048] As mentioned above, as the fixed data path between SGW and virtual anchor point can be utilized repeatedly, when UE, for example, migrates from (or handed over by) the first cell to the second cell, it is unnecessary to establish a new data path, rather, it only needs to establish a second data tunnel between the virtual anchor point and the second cell, namely, an enhanced bi-directional GTP tunnel.

[0049] In some embodiments, the virtual anchor point may include a logic item in a base station located inside the plurality of cells. For instance, the virtual anchor point can be positioned in SeNB.

[0050] In some embodiments, the virtual anchor point may include a logic item in a base station located outside the plurality of cells. For example, the virtual anchor point can be positioned in MeNB.

[0051] It is to be noted that "virtual" means that the implementation of the anchor point is flexible. In other words, any node having computational or storage resources can be configured as a virtual anchor point. Optionally, the function of the virtual anchor point can be enabled and/or disabled with the signaling issued by MME.

[0052] According to embodiments of the present disclosure, method 300 may further include: receiving a changing request of the virtual anchor point issued by the current virtual anchor point before changing from the current virtual anchor point to a new virtual anchor point, and in response to receiving the changing request, establishing the new virtual anchor point.

[0053] Specifically, when it is necessary to switch from the current virtual anchor point to a new virtual anchor point, the current virtual anchor point should first issue changing request to MME which will provide address of the new virtual anchor point to SGW. In the meanwhile, MME will notify the new virtual anchor point to undertake the task of receiving data.

[0054] FIG. 6 illustrates a block diagram 600 of a device for virtual anchor point based data transmission according to the embodiments of the present disclosure. [0055] As shown in FIG 6, the device 600 includes a virtual anchor point establishing unit 610 for establishing a virtual anchor point for a plurality of cells, and a data transmission unit 620 for transmitting data via the virtual anchor point to the UE located in one of the plurality of cells to reduce overhead of cell handover.

[0056] In some embodiments, the data transmission unit 620 includes a link establishing unit configured for transmitting the data to the UE by establishing a link between the virtual anchor point and a corresponding cell among the plurality of cells in which the UE is located.

[0057] In some embodiments, the link establishing unit includes a first detecting unit configured for detecting the UE entering a first cell of the plurality of cells from outside the plurality of cells, and a first link establishing unit configured for in response to detecting the UE entering a first cell of the plurality of cells from outside of the plurality of cells: transmitting data to the virtual anchor point via a fixed data path; establishing a first data tunnel between the virtual anchor point and the first cell; transmitting the data via the first data tunnel from the virtual anchor point to the first cell; and transmitting the data from the first cell to the UE. [0058] In some embodiments, the fixed data path is configured as a reusable data path.

[0059] In some embodiments, the packet head of the data packet transmitted via the first data tunnel includes an MAC address of the virtual anchor point and an MAC address of the first cell. [0060] In some embodiments, the link establishing unit further includes: a second detecting unit for detecting the UE moving from the first cell to the second cell among the plurality of cells; and a second link establishing unit configured for in response to detecting the UE moving from the first cell to the second cell among the plurality of cells: establishing a second data tunnel between the virtual anchor point and the second cell; transmitting the data from the virtual anchor point to the second cell via the second data tunnel; and transmitting the data from the second cell to the UE.

[0061] In some embodiments, the virtual anchor point is configured to include a logic item in a base station located inside the plurality of cells.

[0062] In some embodiments, the virtual anchor point is configured to include a logic item in a base station located outside the plurality of cells.

[0063] In some embodiments, the device 600 further includes an activating unit configured for enabling and/or disabling the function of the virtual anchor point with signaling issued from a mobility management entity.

[0064] In some embodiments, the device 600 further includes: an anchor point changing unit configured for before changing from the current virtual anchor point to a new virtual anchor point, receiving a changing request from the current virtual anchor point; and in response to receiving the changing request, establishing the new virtual anchor point.

[0065] To sum up, embodiments of the present disclosure provide a method and device for virtual anchor point based data transmission. The method includes: establishing a virtual anchor point for a plurality of cells; and transmitting data to the UE located in one of the plurality of cells over the virtual anchor point. With the method, signaling overhead due to frequent handover of the UE in a cell (or base station) can be reduced.

[0066] The above only describes the optional embodiments of the present disclosure which are not used to limit the present disclosure. For those skilled in the art, various modifications and changes can be made to the present disclosure. The scope of protection of the present disclosure is intended to cover various modifications and equivalent arrangements and improvement included in the spirit and principle of the present disclosure.