METHOD AND DEVICE FOR HANDOVER IN MOBILE COMMUNICATION SYSTEM

The present invention refers to various modification may have various can apply in the embodiment which is, in the embodiment example drawing and detailed description specific to the broadcast receiver. However, the present invention is defined with respect to a particular embodiment form which are not included, all changing range of idea and techniques of the present invention, including the water to replacement should understood to evenly. Each drawing are described as well as a component while similar references in a similar.

The present invention refers to, mobile communication system of radio terminal in an oven (User Experience) affecting the user experience high handover according to data transmission time can be reduced delays in a high QoS under public affairs invention number are disclosed.

To this end the present invention refers to, according to a service disconnection time wireless enabled target handover service disconnection with time and time is sent to the terminal is estimated, an estimated time based on neighbor cells of the serving cell selects the wireless terminal handover target cell DNA. According to the present invention, time data transfer to buffer for wireless terminal that the home agent can be selected if target cell for performing handover, a user of the wireless terminal a number of QoS ball be subjected.

The present invention refers to, wireless terminal that the home time for estimating data transfer to time resource information of the serving cell and neighbor cell (Neighbor Cell) can be. The present invention refers to the design and serving cell's base station transmits wireless terminal number under public affairs and off, in order to select the required information is an wireless terminal and a ball from neighbor cells to target cell number can be disclosed.

In hereinafter, the present invention according to in the embodiment with reference to the attached drawing are detailed as follows.

Figure 1 shows a general outline of a handover method in mobile communication system according to one embodiment of the invention to explain the invention as drawing, the serving cell according to time average throughput (130) and, number 1 and number 2 according to alternating time average throughput (110, 120) and upon 2000. In addition in Figure 1 in the embodiment 2 is described as if one personal cells.

The reference also 1, if it is determined that wireless terminal handover is connected to the serving cell, the serving cell wireless terminal and connected and disconnected, a service disconnection time (HIT) is generated. After that the home agent, data stored in the wireless terminal transferred neighboring cells, each neighboring cell available radio access service increasing throughput wireless data stored can be sent to the terminal. The resultant structure is different neighboring radio resources are available, as shown in also 1 through generating a difference is reduced for data transmission, data transmission time through in foot θ1. neighbor cell.

The present invention according to the serving cell, number 1 and number 2 disconnected time generator for neighboring cells (HIT₁ , HIT₂ ) And service disconnection time time wireless is sent to the terminal the data stored neighboring cells (BPDT₁ , BPDT₂ ) Is estimated, the number 1 and number 2 handed over the wireless terminal based on estimation result in target cell determines neighboring cell.

In the present invention is a newly introduced BPDT (Buffered Packets Delivery Time) as general outline, in order to transform the alternating transmission rate introduced by general outline and time dimensions are disclosed. In order that the home agent must be taken into account so that throughput time optimal QoS is being ball number, a service disconnection time transmission rate (throughput) is mutually differ. The present invention refers to the, through in foot BPDT of dependent and time dimensions by introducing, in terms of processing time and throughput time that the home agent can be the same. The higher the throughput BPDT is short, so that throughput is low BPDT generalizations is longer.

Also again return to 1 and, as the aforementioned time BPDT estimated serving cell based on the consideration that the home agent, the wireless terminal determines target cell number 1 and number 2 in handover neighbor cells. As shown in fig. 1, number 1 service disconnection time neighboring cells (HIT₁ ) Neighboring cells is number 2 service disconnection time (HIT₂ ) Longer than, number 1 alternating throughput (110) number 2 is alternating throughput (120) is high enough so that than, alternating BPDT number 1₁ Alternating BPDT is number 2₂ A smaller and, consequently serving cell neighboring cells can be determining target cell number 1.

Serving cell utilizes a radio resource information for estimating a service disconnection time and BPDT neighboring cell, the required information is an ball number from neighbor cells to be subjected.

According to the present invention eventually, handover according to a service disconnection time, taking into account the alternating data transmission speed by determining the wireless terminal handed over target cell, a high QoS can be under public affairs number.

Figure 2 shows a drawing to explain a handover method in mobile communication system according to one embodiment of the invention are also provided, 2 handover method carried out in a serving cell's base station.

The present invention according to a serving cell and the serving cell base station serving cell around radio resource information neighbor cells, QoS information estimation (S210) neighbor cells to each other. QoS information according to a service disconnection time (HIT) and service disconnected handover time of the stored data comprises wireless terminal transmission time (BPDT) information to neighboring cells. The QoS information estimation method, described more specifically in Figure 3.

The QoS information serving cell's base station transmits, to the handover target cell selection (S220) in neighbouring cells to each other. Serving cell's base station transmits in neighbouring cells, a service disconnection time sum of neighboring cell transmission time (BPDT) is minimized handover target cell can be selected.

Figure 3 shows a method in mobile communication system of the present invention also in the embodiment according to drawing to explain as for other handover, 3 handover method carried out in a serving cell's base station.

The present invention according to serving cell's base station, signal strength information received from wireless terminal for neighboring cells (S310) each other. The wireless terminal measures the signal serving cell signal strength information for neighboring cells (RSRP) components.

Serving cell's base station transmits, using signal strength information, determining candidate group of radio terminal handover target cell (S320) each other. The signal strength is greater than the threshold value are neighbor cells, target cell candidate group can be determined.

Serving cell's base station transmits, target cell candidate qualifications with respect to the, QoS information estimation (S330) each other. QoS information as aforementioned, handover according to neighboring cells (HIT) and service disconnected service disconnection time time of the stored data includes information to wireless terminal transmission time (BPDT).

Step S330 serve cell base station provides the target cell candidate group radio resource information, estimates a time when exhaust gas serving of disconnected BPDT candidate neighbor cells.

Serving cell base station as one in the embodiment, to estimate the time of resource information service using a RACH (Random Access Channel) alternating pattern can be disconnected. RACH load an empty, a wireless terminal for connecting neighboring cells can be increased without the outside time, service disconnection time ( ) Is proportional to the load (load) such as [expressions 1] RACH form equations can be modeling.

Where, ρ is exhibit RACH load, a and b may vary in accordance with the constants is in the embodiment are disclosed.

Serving cell base station estimating BPDT compensated, target cell candidate group radio resource information, calculates available throughput for transmitting data stored. The available throughput and disconnected in which, a BPDT estimates.

One in the embodiment serve as cell base station, radio resources as available, data transmission may be used in an number of subcarriers (s), are determined according to MCS (Modulation and Coding Scheme, h) contains an encoding ratio (code rate, R_h ), The ncand size (constellation size, M_h ), OFDM symbol period (duration, S_OFDM ), Resource block (resource block) in OFDM symbol number (N_RB ) Available throughput can be calculated using. Serving cell base station based on the aforementioned available radio resources, available throughput can be calculated, as an example [equations 2] using available throughput ( ) Can be calculated.

The serving cell base station services using [equations 3] sum of time disconnected BPDT ( ) Can be estimated.

[Equations 3] is from the group consisting of computing an estimate for the candidate target cell as a neighbor cell i expressions, wherein, Terms corresponding to a BPDT, Are disclosed. And As shown in is also 1, transmitting data to other wireless terminals used and throughput, Data is stored in a buffer for transmission to a wireless terminal that throughput added throughput among others. and [Equations 2] based on each radio resource is available through can be calculated.

Data not transmitted during a service disconnection time, prevented BPDT time, BPDT is, not the amount of data transmitted during a service disconnection time (B) and, BPDT time data to be transmitted can be calculated using the same amount (A) that conditions. For example, in Figure 1, number 1 (HIT1) amount of data transmitted during alternating service disconnection time not service disconnection time (HIT1) and throughput of the serving cell (110) can be represented by multiplication of the, number 1 BPDT cells₁ The amount of transmit time organized, for transmitting data stored throughput ( ) And, BPDT₁ Can be represented by multiplication of the. The throughput of the serving cell (110) is If, the aforementioned conditions BPDT₁ the Such as can be represented.

3 again and also seemingly functions as, serving cell's base station, was estimated in step S330 QoS information, handover target cell selection (S340) and candidate target cell group, handover target cell be indication for handing over a wireless terminal.

Serving cell's base station, service disconnection time transit time of said sum is minimized can be selected from the group consisting of neighboring cell candidate target cell handover target cell. At this time, the serving cell base station corresponding to the calculated Pareto (pareto) [expressions 3] forms, handover can be selecting a target cell.

On the other hand, according to the present invention, delayed value and delay threshold HOL handover target cell (Head Of Line) based on wireless terminal, the wireless terminal determines the priority of the resource assignments can. I.e., the present invention increase the handover handover target cell are determined according to the wireless terminal, the wireless terminal is the wireless terminal to the handover target cell BPDT for assigning a high resource allocation can be minimize.

HOL handover target cell delay value is a wireless terminal for transmitting a first data packet queue delay values, as compared to other wireless terminals for transmitting and receiving data connected to the handover target cell already handed over a radio terminal HOL is essentially larger than the delay value, the wireless terminal is larger delay HOL handover target cell by assigning a high priority, handover wireless terminal can be reduce BPDT first radio resources are allocated.

In addition delay threshold is wireless terminal is acceptable delay threshold as requested emergency processing of radio terminal transmits and receives data must do is set the lower threshold may be delay. The handover target cell delay threshold low priority by assigning a large wireless terminal, the wireless terminal is assigned a lower priority emergency transmitting fire blood grudge of radio resources by efficiency of radio resources can be.

I.e., flavor thereto, HOL delayed value which is proportional to a size of the handover target cell, by determining priority resource allocation to inversely proportional to the delay threshold, and to reduce the BPDT be efficiently utilize radio resources.

Figure 4 shows a device according to one embodiment of the invention therefore to account for surface handover in mobile communication system are disclosed.

The reference 4 also, the present invention according to handover device includes information reception portion receives (410), candidate group decision unit (420), information estimating section (430) and target cell selection unit (440) having a predetermined wavelength. The aforementioned correlation of the serving cell or serving cell base station handover method included in the handover device can be performed.

Information reception portion receives (410) from a wireless terminal receives a signal strength information for neighboring cells.

Candidate group decision unit (420) using the signal strength information, determines candidate group of radio terminal handover target cell.

Information estimating section (430) to candidate qualifications with respect to the target cell, QoS information estimates. Information estimating section (430) is more specifically target cell candidate group radio resource information, a service disconnection time estimating HIT estimating section and target cell candidate group radio resource information, target cell candidate qualifications with respect to predict the available throughput, in which available throughput and service disconnected, BPDT estimation for estimating transmission time (BPDT) having a predetermined wavelength.

Target cell selection unit (440) is QoS information, target cell selects candidate group handover in a target cell. Target cell selection unit (440) is the transit time of said neighboring cell service disconnection time sum is minimized candidate target cell can be selected from the group consisting of handover target cell.

Aforementioned technological content is translated various computer means embodied in the form of computer-readable medium recording program instructions can be performed can be. Said computer-readable medium program instructions, data files, data structure or the like can be either alone or in combination. In the embodiment specifically designed and constructed for said medium recorded programs command is computer software that may be enable or ones publicly known to one skilled in the disapproval. Examples of computer-readable recording medium hard disk, floppy disk and magnetic medium (magnetic media) such as tapes, CD-a ROM, DVD (optical media) such as optical recording medium, such as magnetic - flop mote curl disk (floptical disk) optical medium (magneto-a optical media), and ROM (ROM), ram (RAM), such as flash memory and executing program instructions stored to hardware device specially configured multiple myelomas are included. Examples of such as machine code by a compiler program instructions are made can be carried out by a computer as well as interpreter order currently used in conventional language code comprises brilliance. In the embodiment of the hardware device perform operations can be configured to operate as one or more software modules, and vice-versa are disclosed.

In the present invention than in the embodiment and in particular components such as described by the drawing of the present invention evaluates a defined and specific overall than sophisticated understanding but this number to aid presents ephemeral, in the embodiment of the present invention refers to said limited to has , the present invention with the various conventional knowledge from the substrate and flawless NaOCl such modifications and deformable disclosed. Thus, in the embodiment of the present invention does not require any limited idea is described in which WD, as well as the claim or claim carry evenly on all that is equivalent deformation will that category of event belonging to the present invention.