JP2003333660A - Mobile communication system and method for soft handover during compressed mode execution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication system capable of soft handover of homogeneous frequencies during execution of a compressed mode. <P>SOLUTION: When the compressed mode is started, a mobile terminal 4 measures communication state of heterogeneous frequencies or heterogeneous systems in parts of gaps and detects the radio state of homogeneous frequencies and transmits a handover request of cells 104 under a radio base station device 3 of the same frequency to a radio base station controller 1. The radio base station controller 1 utilizes an HFN being used in secret in order to continues the compressed mode and calculates a position of a gap (CNF) at a present time in accordance with a difference from the start time of the compressed mode and indicates the same gap pattern as a radio base station device 2 to the radio base station device 3. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mobile communication system,
Radio base station control device and compres used for them
TECHNICAL FIELD The present invention relates to a soft handover method during execution of a sed mode, particularly in a mobile communication system.
d) Related to soft handover during execution of Mode.

[0002]

2. Description of the Related Art Conventionally, in a mobile communication system, a handover between different frequencies and different systems is performed in consideration of a currently used frequency, a boundary of the system, a same frequency, and a case where the radio wave condition of the system is bad.

However, since the mobile terminal cannot measure a plurality of frequencies at the same time, the mobile terminal observes the communication state of different frequencies or different systems.
It is necessary for the radio base station to provide a gap (GAP) and transmit data to the mobile terminal. The data transmission state from the radio base station to the mobile terminal in this gap is
This is called the pressed Mode state.

In the Compressed Mode state, when a certain condition is satisfied, a handover between different frequencies and different systems is carried out. However, if the radio condition of the current frequency deteriorates before the condition is satisfied, It is necessary to perform a soft handover to another cell.

Hereinafter, this Compressed Mod
The e state will be described. The radio base station control device sets the cell to the radio base station device in the compressed mode.
ask e to do it. At that time, the radio base station controller gives an instruction for a gap start pattern. Similarly to the above, the radio base station controller sends the mobile terminal a Comp
It indicates the start of the pressed mode and the pattern of the gap.

When the compressed mode state is started, the mobile terminal measures the communication state of the different frequency or the different system in the gap part. Compr
In the ESSED MODE state, the mobile terminal detects a radio state of the same frequency and transmits a handover request to the radio base station control device for cells under the control of the radio base station device of the same frequency.

In the radio base station controller, Compress
In order to continue the ed mode, it is necessary to instruct the radio base station device to the same gap pattern. This is because the mobile terminal recognizes the position of the gap at the same timing in both the cell under the control of the radio base station device and the cell under the control of another radio base station device of the handover destination, and measures the radio condition of the system, Other than that, it is for receiving downlink data.

[0008]

However, in the above-described conventional mobile communication system, as shown in FIG. 7, when the gap interval is not a power of 2, CFN (Con
injection Frame Number: 0-25
6: 1 FN = 10 ms), the same C at the next timing
Not necessarily FN, even if CFN = 10 on the first lap, 2
CFN = 12 on the first lap, which is Compr
There is a problem that a soft hand handover with the same frequency cannot be performed during the ESSED MODE.

Therefore, an object of the present invention is to solve the above-mentioned problems and to carry out soft handover of the same frequency in a compressed mode, a radio base station controller and a compr used for them.
An object of the present invention is to provide a soft handover method during execution of the ESSED MODE.

[0010]

In a mobile communication system according to the present invention, a radio base station provides a gap in order to realize a handover between different frequencies and different systems in a Compressed Mode state, and a data is transmitted toward a mobile terminal. Is a mobile communication system in which a mobile terminal observes a communication state of a different frequency or a different system,
The synchronization information of the gap at that time is recognized based on the elapsed time from the start time of the Compressed Mode, and the same gap pattern as that of the handover source radio base station is set to the handover destination radio base station based on the gap synchronization information. Instructing.

A radio base station controller according to the present invention is a Co
In the pressed mode state, different frequencies,
In order to realize a handover between different systems, a wireless base station provides a gap, transmits data to the mobile terminal, and the mobile terminal observes a different frequency or a communication state of the different system in the mobile communication system. A radio base station controller for controlling a station, comprising:
Responsive to the synchronization information of the gap at that time based on the elapsed time from the start time of the ESSED MODE, and instructing the handover destination wireless base station of the same gap pattern as the handover source wireless base station based on the gap synchronization information is doing.

Compressed Mo according to the present invention
In the soft handover method in progress of de, the wireless base station provides a gap to transmit data to the mobile terminal in order to realize handover between different frequencies and different systems. A soft handover method during execution of a compressed mode for observing a communication state, the method comprising:
A step of recognizing the synchronization information of the gap at that time based on the elapsed time from the start time of the ssed Mode, and a radio base station of the handover destination having the same gap pattern as the radio base station of the handover source based on the synchronization information of the gap. And the step of directing to.

That is, the mobile communication system of the present invention is
It is intended to provide a configuration capable of realizing handover between different frequencies and different systems while maintaining highly reliable communication quality.

More specifically, in the mobile communication system of the present invention, a radio base station is provided with a gap (GAP) in order to realize handover between different frequencies and different systems.
Is provided and data is transmitted to the mobile terminal, and the mobile terminal observes a communication state of a different frequency or a different system (Compressed Mode state).

In the mobile communication system of the present invention, this Co
In the pressed mode state, when a certain condition is satisfied, a handover between different frequencies and different systems is performed. However, if the radio condition of the current frequency deteriorates before the condition is satisfied, the software to another cell is softened. Handover needs to be performed.

Therefore, in the mobile communication system of the present invention,
By realizing the softover in the Compressed Mode state, it is possible to keep the communication quality with high reliability.

That is, according to the present invention, the radio base station controller recognizes the gap synchronization information at the time based on the elapsed time from the time of starting the Compressed Mode, thereby performing the different frequency hard handover and the different system hard handover. Compressed to achieve
Soft handover of the same frequency in Mode becomes possible.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a mobile communication system according to an embodiment of the present invention. Figure 1
In, a radio base station control device (RNC: Radio Network Control)
1) and wireless base station devices (NodeB) 2 and 3
And an area (cell) 101 accommodated by the base station devices 2 and 3
~ 106 and a mobile terminal (UE: User Equipm)
ent) 4 and.

The radio base station control device 1 issues a control request to the radio base station device 2 and the mobile terminal 4 in order to keep the communication quality with high reliability. Each of these devices operates roughly as follows.

In these devices, in consideration of the currently used frequency, the boundary of the system, or the same frequency, and the case where the radio wave condition of the system is bad, the handover between different frequencies and different systems is performed.

However, since the mobile terminal 4 cannot measure a plurality of frequencies at the same time, a gap (GAP) is set in the radio base station apparatus 2 in order for the mobile terminal 4 to observe a communication state of a different frequency or a different system. Provided,
It is necessary to send data to the mobile terminal 4. This data transmission state is called a Compressed Mode state.

The radio base station controller 1 is a radio base station device 2
In contrast, the cell 103 is set to a compressed mod.
ask e to do it. At that time, the radio base station control device 1 instructs the radio base station device 2 about a gap start pattern. Similarly, the radio base station control device 1 also instructs the mobile terminal 4 to start the compressed mode and the pattern of the gap.

When the compressed mode state is started (process a in FIG. 1), the mobile terminal 4 measures the communication state of the different frequency or the different system at the gap. In the compressed mode state, the mobile terminal 4 detects a radio state of the same frequency and transmits a handover request to the radio base station controller 1 for the cell 104 under the radio base station device 3 of the same frequency.

In the radio base station controller 1, Compres
In order to continue the sed mode, the wireless base station device 3
Need to indicate the same gap pattern to.
This is because the mobile terminal 4 has a cell 10 under the control of the radio base station device 2.
This is because both the cells 3 under the radio base station device 3 recognize the position of the gap at the same timing to measure the radio state of other frequencies and the system, and otherwise receive downlink data.

However, when the gap interval is not a power of 2, CFN (Connection F
frame Number: 0-256: 1FN = 10m
s), the CFN does not always become the same CFN at the next timing. Even if CFN = 10 in the first lap, CFN = 1 in the second lap.
There is a problem that it deviates from 2.

Therefore, the HFN (Hyper Frame Number, C) is used in secret to prevent the control signal and the user information from being illegally intercepted in the wireless section.
It is possible to calculate the gap position (CFN) at the present time from the difference (using HFN and CFN) from the start of the Compressed Mode by utilizing (1 count-up when the FN makes one round).

With respect to the HFN start timing, even in the case where the confidentiality is not executed, the HFN is activated from the time when the Connection is established, that is, the time when the CFN count is started.

FIG. 2 is a diagram showing the pattern parameters of the compressed mode. In FIG. 2, C
The pattern parameter of the compressed mode includes TG (Transmission Gap) patterns (patterns) 1 and 2, and the gap TG1.
Includes TG2. Here, the length of the gap TG1 is TGL (Transmission Gap Length).
th) 1 and the length of the gap TG2 is TGL2.

The repeating pattern of the TG patterns 1 and 2 is TGPL (Transmission Gap Len).
gth) (= TGPL1 + TGPL2).
Further, in the gap TG1 between the TG patterns 1 and 2, T
GSN (Transmission Gap Star)
toning slot number) is transmitted. From this TGSN to before the gap TG2, TGD (Tr
(Ansmission Gap Distance).

FIG. 3 is a sequence chart showing the operation between the radio base station apparatuses 2 and 3 of FIG. 1, and FIGS. 4 to 6 are diagrams showing the pattern parameters of the Compressed Mode according to an embodiment of the present invention. FIG. 5 shows Compressed Mo when the gap interval is a power of 2.
6 shows a pattern parameter of de, and FIG. 6 shows Compressed M when the gap interval is not a power of 2.
The pattern parameter of ode is shown. These Figure 1
The operation of the entire mobile communication system according to the embodiment of the present invention will be described with reference to FIG.

First, at the time of starting the compressed mode (A1 in FIG. 3), the radio base station controller 1 has HFN (CM HFN) at present and CFN (CM CF).
N) and also information about the gap.

A1 in FIG. 3 is Compressed Mo.
This is a de starting process, and in this A1, the radio base station control device 1 notifies the radio base station device 2 of RL (Radio Li
nk) Reconfiguration Prepa
re [NBAP (NodeB Application
Protocol)] is transmitted. On the other hand, the radio base station apparatus 2 sends the RL Reco
Since nfigure Ready (NBAP) is transmitted, the radio base station control device 1 transmits the radio base station device 2 to the radio base station device 2.
RL Reconfiguration Commi
Returns t (NBAP).

Further, the radio base station controller 1 is equipped with a mobile terminal 4
On Physical CH (Channel) Rec
configuration [RRC (Radio Re
source Control)] is transmitted.

Then, the mobile terminal 4 informs the radio base station controller 1 of Physical CH Reconfigure.
of the mobile station 4, the radio base station controller 1 sends the mobile terminal 4 a Measurement (RRC).
t Control (RRC) (Inter-System
Sending a measurement regarding em). As a result, the wireless base station device 2 and the mobile terminal 4 are
The Lessed Mode is starting up.

Next, the mobile terminal 4 detects the radio condition of the same frequency, and the cell 10 under the control of the radio base station device 3 of the same frequency.
4 is requested to the radio base station controller 1 (A2 in FIG. 3). In A2 of FIG. 3, the mobile terminal 4 detects that the threshold of Event 1A is exceeded, and
This is performed by transmitting a measurement report (RRC) (a request to add the cell 104 under the control of the radio base station device 3) to the radio base station control device 1.

In the radio base station controller 1, Compres
HFN at that point to continue the sed Mode
(Current HFN), CFN (Current
CFN) is read and HFN (C
CM (Compressed Mode) Con using the difference between MHFN) and CFN (CM CFN)
Calculate the formation CFN. In addition, in the radio base station control device 1, the “CM Co
nfigure Change CFN "(A3 in FIG. 3).

In A3 of FIG. 3, the radio base station control device 1 instructs the radio base station device 3 to perform RL Setup Request.
est (NBAP) is transmitted. On the other hand, the wireless base station device 3 causes the wireless base station control device 1 to perform RL Setup.
Returns Response. In addition, the radio base station control device 1
Transmits to the wireless base station device 2 as an Establish Request.
st [ALCAP (Access Link Cont
[Roll Application Part)] is transmitted. On the other hand, the wireless base station device 3 sends to the wireless base station control device 1 the Establish Confirm (ALC).
AP) is returned.

"CM Configuration C
When the synchronization information is provided to the wireless base station device 3 by using the change CFN ″, the processing outline of the wireless base station control device 1 needs to be performed as follows.

First, the radio base station controller 1 uses Compr.
CFN / HFN (CM at the time of esseed Mode start
CFN / CM HFN) is acquired and saved [Process (1)]. Then, the radio base station control device 1
nt CFN and CurrentHFN are acquired [process (2)].

After this, the radio base station control device 1
Frame N from the start of the pressed mode
number (FN), FN = (HFN-CM HFN) * 256 + CFN-C
Calculation is performed using the formula M CFN [Processing (3)].

In this case, the length of the repeating pattern is TGPL = TGPL1 + TGPL2 [Processing (4)].

From the above processing, Last passed
CFN is Last passed CFN = CFN- (FN) m when CFN ≧ (FN) mod (TGPL).
If od (TGPL) CFN <(FN) mod (TGPL), Last passed CFN = 255-[(FN)
mod (TGPL) -CFN] [Processing (5)].

For example, HFN = 3, CFN = 24, CM
HFN = 1, CM CFN = 230, TGPL = 30
In the case of, it is performed as follows.

The radio base station controller 1 sets the value of FN to [Processing (5-1)].

Then, the radio base station controller 1 (FN)
mod (TGPL) is calculated as (FN) mod (TGPL) = (306) mod (30) = 6 [Process (5-2)].

The radio base station controller 1 has CFN ≧ (FN)
Since it is a mod (TGPL), "CM Config
The value to be set in the Duration Change CFN ”is calculated as“ CM Configuration Change CFN ”= CFN− (FN) mod (TGPL) = 18 [Process (5-3)].

In the radio base station device 3, "CM Config"
The compressed mode can be executed at the same gap timing as that of the radio base station apparatus 2 by instructing the “Change Change CFN” (A4 in FIG. 3).

In A4 of FIG. 3, the radio base station controller 1 instructs the mobile terminal 4 to set ActiveSet Update.
(RRC) is transmitted. Then, the mobile terminal 4 informs the radio base station control device 1 of Active Set Update.
Since the Complete (RRC) is returned, the radio base station controller 1 notifies the mobile terminal 4 of the Measurement Consent.
send troll (RRC). As a result, in the radio base station device 3 and the mobile terminal 4, the Compressed Mod is performed at the same gap timing as the radio base station device 2.
e can be performed.

In the radio base station controller 1, Compre
In order to continue the ssed Mode, it is necessary to instruct the radio base station device 3 to the same gap pattern as the radio base station device 2, as shown in FIG. This is because the mobile terminal 4 recognizes the position of the gap at the same timing with the cell 103 under the radio base station device 2 and the cell 104 under the radio base station device 3 and measures the radio frequency of other frequencies and the system. Other than this is for receiving downlink data.

However, as shown in FIG. 6, when the gap interval is not a power of 2, CFN (Conne
action Frame Number: 0-256:
1FN = 10 ms) and the same CFN at the next timing
However, there is a problem that CFN = 10 in the first lap and CFN = 12 in the second lap.

Therefore, the HFN (H
yper Frame Number, CFN makes one count up when it makes one round)
Differences from the start of essed Mode (HFN, CF
The position of the current gap (CFN) can be calculated from (using N).

At this HFN start timing, even in the case where the concealment is not executed, the HFN is activated from the time when the Connection is established, that is, the time when the CFN count is started.

In this way, the Compressed Mo
Since the radio base station controller 1 can recognize the synchronization information of the gap at that time based on the elapsed time from the start time of de, different frequency hard handover and different system hard handover can be realized. Co
Soft handover of the same frequency can be performed during the pressed mode.

[0054]

As described above, according to the present invention, Comp
In the depressed mode state, a radio base station provides a gap and transmits data to a mobile terminal in order to realize handover between different frequencies and different systems,
In a mobile communication system in which a mobile terminal observes a communication state of a different frequency or a different system, a Compress
d) The synchronization information of the gap at that time is recognized based on the elapsed time from the start time of d Mode, and the same gap pattern as that of the handover source radio base station is instructed to the handover destination radio base station based on the gap synchronization information. By doing so, it is possible to obtain the effect that soft handover of the same frequency can be performed during the compressed mode.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a mobile communication system according to an embodiment of the present invention.

FIG. 2 is a diagram showing pattern parameters of Compressed Mode.

FIG. 3 is a sequence chart showing an operation between the wireless base station devices of FIG.

FIG. 4 is a Compressed according to an embodiment of the present invention.
It is a figure which shows the pattern parameter of Mode.

FIG. 5 is a Compressed according to an embodiment of the present invention.
It is a figure which shows the pattern parameter of Mode.

FIG. 6 is a Compressed according to an embodiment of the present invention.
It is a figure which shows the pattern parameter of Mode.

[Explanation of symbols]

1 Radio base station controller 2, 3 wireless base station device 4 mobile terminals 101-106 area (cell)

Claims (9)

[Claims] 1. In a compressed mode state, a radio base station establishes a gap for transmitting a handover between different frequencies and different systems, and data is transmitted to the mobile terminal, and the mobile terminal receives the different frequency or different system. Is a mobile communication system for observing the communication state of the wireless communication device, the synchronization information of the gap at that time is recognized based on the elapsed time from the start time of the Compressed Mode, and the handover source radio base station is based on the synchronization information of the gap. A mobile communication system, characterized by instructing a handover destination radio base station of the same gap pattern as that of a station. 2. A radio base station controller for controlling the radio base station, wherein the radio base station controller is a CFN (Connecti).
on Frame Number) and HFN (Hyper Frame Number), which is used for concealment to prevent unlawful interception of control signals and user information in a wireless section, and counts up 1 when the CFN makes one round.
r) and the Compressed Mode
The mobile communication system according to claim 1, wherein the synchronization information of the gap is recognized by calculating the position of the gap at the present time from the difference from the start time. 3. The mobile communication system according to claim 2, wherein the HFN is activated from the time when the counting of the CFN is started, independently of the concealment. 4. In the compressed mode state, in order to realize a handover between different frequencies and different systems, a radio base station establishes a gap and transmits data to the mobile terminal, and the mobile terminal transmits the different frequency or different system. A radio base station control device for controlling the radio base station in a mobile communication system for observing the communication state of, recognizing synchronization information of a gap at that time based on an elapsed time from the time point of starting the Compressed Mode, A base station control device characterized by instructing a handover destination radio base station the same gap pattern as a handover source radio base station based on the gap synchronization information. 5. A CFN (Connection Fra)
meNumber), a control signal and user information are used in secrecy to prevent unlawful interception in a wireless section, and the HFN increments by 1 when the CFN makes one round.
5. The base station according to claim 4, wherein the synchronization information of the gap is recognized by calculating the position of the gap at the present time from the difference from the start of the Compressed Mode by using (HyperFrame Number). Control device. 6. The base station controller according to claim 5, wherein the HFN is activated independently of the concealment from the time when the counting of the CFN is started. 7. A radio base station transmits a data to a mobile terminal in order to realize a handover between different frequencies and different systems, and the mobile terminal observes a communication state of a different frequency or a different system. Compre
A soft handover method during execution of ssed Mode, which comprises recognizing synchronization information of a gap at that time based on an elapsed time from the time of starting the Compressed Mode, and a handover source radio base based on the synchronization information of the gap. And a step of instructing a handover target radio base station of the same gap pattern as that of the station. 8. A radio base station control device for controlling the radio base station comprises a CFN (Connection Frame).
Number), a control signal and user information are used in secrecy to prevent unlawful interception in a wireless section and the CFN makes one count when the HFN (H
8. The soft handover according to claim 7, wherein the synchronization information of the gap is recognized by calculating the position of the gap at the present time from the difference from the start of the Compressed Mode by utilizing the Y. Frame Frame Number). Method. 9. The soft handover method according to claim 8, wherein the HFN is activated independently of the concealment from the time when the counting of the CFN is started.