U.S. patent application number 11/730546 was filed with the patent office on 2007-08-02 for mobile communication system using a downlink shared channel.
This patent application is currently assigned to FUJITSU LIMITED. Invention is credited to Eiji Ikeda, Kazunari Kobayashi, Tomonori Kumagai, Tetsuo Tomita.
Application Number | 20070177563 11/730546 |
Document ID | / |
Family ID | 29606636 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070177563 |
Kind Code |
A1 |
Ikeda; Eiji ; et
al. |
August 2, 2007 |
Mobile communication system using a downlink shared channel
Abstract
A method of mobile communication at a base station includes
transmitting to a mobile station, identifying information for
multicast data to be transmitted to the mobile station and
transmitting the multicast data on a shared channel to the mobile
station, wherein the data is identified by the information.
Inventors: |
Ikeda; Eiji; (Kawasaki,
JP) ; Kumagai; Tomonori; (Kawasaki, JP) ;
Tomita; Tetsuo; (Kawasaki, JP) ; Kobayashi;
Kazunari; (Kawasaki, JP) |
Correspondence
Address: |
BINGHAM MCCUTCHEN LLP
2020 K Street, N.W.
Intellectual Property Department
WASHINGTON
DC
20006
US
|
Assignee: |
FUJITSU LIMITED
|
Family ID: |
29606636 |
Appl. No.: |
11/730546 |
Filed: |
April 2, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10999206 |
Nov 24, 2004 |
|
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|
11730546 |
Apr 2, 2007 |
|
|
|
PCT/JP02/05340 |
May 31, 2002 |
|
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|
10999206 |
Nov 24, 2004 |
|
|
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Current U.S.
Class: |
370/338 |
Current CPC
Class: |
H04W 72/005 20130101;
H04W 72/1289 20130101; H04W 72/042 20130101; H04W 4/06 20130101;
H04W 72/1268 20130101 |
Class at
Publication: |
370/338 |
International
Class: |
H04Q 7/24 20060101
H04Q007/24 |
Claims
1. A method of mobile communication at a base station comprising:
transmitting to a mobile station, identifying information for
multicast data to be transmitted to the mobile station; and
transmitting the multicast data on a shared channel to the mobile
station, wherein the data is identified by the information.
2. The method of claim 1, wherein the shared channel is same
channel among a plurality of mobile stations.
3. The method of claim 1, wherein at least a portion of the data
transmitted on the shared channel is for a plurality of mobile
stations.
4. A method of mobile communication at a mobile station comprising:
receiving from a base station, on a signaling channel dedicated to
the mobile station, identifying information to be transmitted to
the mobile station; and receiving multicast data on a shared
channel from the base station, wherein the data is identified by
the information received.
5. The method of claim 4, wherein the shared channel is same
channel among a plurality of mobile stations.
6. The method of claim 4, wherein at least a portion of the data
transmitted on the shared channel is for a plurality of mobile
stations.
7. A method of mobile communication comprising: transmitting from a
base station, identifying information for multicast data to be
transmitted to the mobile station; receiving at the mobile station,
the information from the base station; transmitting the multicast
data from the base station on a shared channel, wherein the data is
identified by the information; and receiving at the mobile station
the data on the shared channel by the information received.
8. The method of claim 7, wherein the shared channel is same
channel among a plurality of mobile stations.
9. The method of claim 7, wherein at least a portion of the data
transmitted on the shared channel is for a plurality of mobile
stations.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 10/999,206, filed Nov. 24, 2004, which is a continuation of
International Application No. PCT/JP02/05340, filed May 31, 2002,
which are hereby incorporated by reference herein in their
entirety.
TECHNICAL FIELD
[0002] The present invention relates to a communication method and
device in a mobile communication system using a downlink shared
channel (DSCH).
BACKGROUND ART
[0003] In recent years, development of CDMA (Code Division Multiple
Access) communication systems has proceeded apace, and the need to
shift to Wideband-CDMA (W-CDMA) systems that provide a wider
bandwidth than previously in order to exchange not merely voice but
also large-capacity data such as images or video at high speed, and
with high quality and efficiency has increased.
[0004] Communication systems adapted to these demands are generally
called third generation mobile communication systems and the
standards relating thereto are co-coordinated by the 3GPP (Third
Generation Partnership Project), which is the world standardization
organization; introduction of such systems has already begun.
[0005] In 3GPP, a DSCH (downlink shared channel) is defined as a
downlink channel that is used in shared fashion by a plurality of
mobiles (see 3GPP TS 25.427, TS 25.435). With DSCH, a single
channel can be shared by a large number of mobiles and flexible
power control can be achieved. In this way, high-speed and
high-efficiency data communication can be implemented with limited
wireless resources so the importance of this technique is expected
to increase in the future.
[0006] FIG. 1A to 1C show an outline of downlink data communication
(communication to mobiles) in a communication system employing
DSCH. This system comprises a core network 100, which is a wired
network, a wireless network control device 101, base stations 102
and mobiles 103.
[0007] DSCH is the name given to the channel between the wireless
network control device 101 and the base stations 102; this DSCH is
mapped onto a PDSCH (physical downlink shared channel), which is
one of the physical channels on wireless.
[0008] Also, for a single mobile 103, there is a single
individually assigned channel, which is called a dedicated channel
(DCH) between the wireless network control device 101 and a base
station 102, and which is called a dedicated physical channel
(DPCH) on wireless. The mapping of the channels is defined in 3GPP
TS 25.301.
[0009] As shown in FIG. 1A, when data is transmitted on a DSCH, it
is necessary to transmit control data, called signaling, on the
DPCH. The signaling data is used to report to the mobile 103
whether or not data is present on the PDSCH, at a timing
corresponding to this signaling.
[0010] Specifically, the mobile 103 is not always in receiving
condition in regard to the PDSCH but only receives data on the
PDSCH if signaling data has been received on the DPCH.
[0011] The ability to receive data on the DSCH therefore only
exists in the case where a dedicated CH is set up in respect of the
mobile 103; data cannot be received on the DSCH in the idle state
or in a condition in which a dedicated channel is not set up. It
should be noted that the mobile 103 is normally able to receive
signaling data on the DPCH.
[0012] Mapping of the aforesaid signaling data wirelessly onto DPCH
is as described above. Two methods are laid down between the
wireless network control device 101 and base station 102. In one
case, data is transmitted on DCH. In the other case, data is
transmitted on another channel established for the signaling.
[0013] Thereupon, after the mobile 103 has received the signaling
data, in order to start preparation for receiving the DSCH, the
DSCH data must be transmitted later than the signaling by a delay
time .DELTA.T.
[0014] The DSCH data is transmitted in accordance with a standard
timing that is set for each sector, so the reception timings
thereof are the same for the mobiles 103. In contrast, the DPCH
reception timings are different for each of the mobiles 103.
Consequently, the aforesaid delay time .DELTA.T also differs for
each mobile 103. The wireless network control device 101 must
therefore perform transmission timing control of the signaling
data, in consideration the delay time .DELTA.T for each mobile
103.
[0015] It should be noted that the delay time a T is respectively
reported to the wireless network control device 101, base station
102 and mobile 103 by the application at the time point of call
set-up.
[0016] Also, as shown in FIG. 1B, the identifier ID 104-2 that is
applied to each mobile is stored in the DSCH frame 104 in addition
to the user data 104-1. This is necessary in order that the DSCH
frame 104 should be correctly transmitted to a specified mobile
103.
[0017] For this reason, as shown in FIG. 1C, transmission can only
be effected in respect of a single mobile 103 in a single
transmission slot; a DSCH frame that is transmitted in this
transmission slot cannot be simultaneously received by a plurality
of mobiles 103.
[0018] FIG. 2 shows an example of the processing sequence in DSCH
transmission. When the wireless network control device 101 receives
(step 31) user data 104-1 from the core network 100, it generates a
DSCH frame 104 (processing step P1) from the information that was
already set as the user data 104-1. After this, the transmission
timing of the DSCH frame 104 is determined (processing step
P2).
[0019] Then, after the signaling data has been generated
(processing step P3), the transmission timing of the signaling data
is determined (processing step P4) using the aforesaid delay time a
T, from the DSCH frame transmission timing. The signaling data is
transmitted (step S2) to the mobile 103 through the base station
102 in accordance with the signaling transmission timing.
[0020] When a mobile 103 receives signaling data, it becomes aware
of the existence of a DSCH frame that is to be received on the
PDSCH, and starts preparation to receive this DSCH frame
(processing step P5). After this, the wireless network control
device 101 transmits the DSCH frame to the mobile 103 (step S3)
through the base station 102 in accordance with the DSCH frame
transmission timing.
[0021] After receiving this DSCH frame, the mobile 103 compares the
mobile identifier ID 104-2 in the data with its own ID (processing
step P6) and, if they agree, performs subsequent data processing.
Also, if the mobile ID 104-2 in the DSCH frame data does not agree
with its own ID, it discards this DSCH frame (processing step
P7).
DISCLOSURE OF THE INVENTION
[0022] As described above, since a single DSCH channel is shared by
a large number of mobiles 103, high-speed/high efficiency wireless
communication can be achieved. However, as shown in FIG. 1,
transmission can only be effected in respect of a single mobile 103
in a single transmission slot. Thus, the DSCH frame that is
transmitted in the transmission slot (see FIG. 1C) cannot be
simultaneously received by a plurality of mobiles 103.
[0023] In the future, with improvements in transmission rate, it is
planned to perfect a large-capacity service providing music
delivery and video delivery, but when DSCH is employed in the
current technology, when distributing the same data to a plurality
of mobiles 103 in this way, because of the restrictions described
above, it is necessary to transmit exactly the same data to as many
mobiles as are to receive it. There is therefore considerable waste
from the point of view of efficiency of use of wireless and wired
transmission channels and it is thought that, as a result of the
accumulation of the amount of data destined for the mobiles, the
DSCH rate will be adversely affected and communication quality will
tend to be lowered.
[0024] Although this problem may apparently be solved by fortifying
the infrastructure, this results in increased costs of the
infrastructure and so in increased communication charges and cannot
but put a brake on future diversification and development of
service modes.
[0025] An object of the present invention is therefore to provide
an efficient communication method and device based on the current
DSCH technique, whereby diverse services, in particular
distribution system services (multi-cast services) can be
implemented in future by improving the communication rate.
[0026] Furthermore, from the point of view of development costs and
development time, it is important to take great pains not to alter
the existing 3GPP regulations. Also, DSCH has the characteristic
feature that reception is only possible when a dedicated CH has
been setup in respect of a mobile. In view of this aspect, an
object of the present invention is to provide a communication
method and device aimed at implementing further new services
wherein for example data distribution is performed on DSCH only
during telephone service.
[0027] A characteristic feature of a communication method and
device according to the present invention capable of meeting this
object and comprising a wireless network control device, base
stations and mobiles on which there is respectively installed one
or more communication protocol as specified by for example 3GPP is
the performance of multi-cast communication of data in respect of
one or more mobiles using DSCH.
[0028] In addition, said wireless network control device according
to the present invention is characterized by the provision of a
functional section that processes DSCH internally and, in addition,
the provision of table means that stores various types of setting
information relating to DSCH communication and DSCH multi-cast
communication. Using these items of information, multi-cast
communication (including unicast communication) is implemented
using DSCH in respect of one or more mobiles.
[0029] Also, a base station in accordance with the present
invention comprises a function of transmitting DSCH data and/or
said signaling data received from the wireless network control
device to the mobiles through a wireless circuit.
[0030] Furthermore, in addition to the ordinary functions, a mobile
may comprise an identification function in respect of whether data
on the DSCH is unicast or multicast.
[0031] Further features of the present invention will become clear
from embodiments of the present invention that are described below
with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a view showing an outline of downlink data
communication (communication to mobiles) in a communication system
employing DSCH.
[0033] FIG. 2 is a view showing an example of a processing sequence
during DSCH transmission.
[0034] FIG. 3 is a view given in explanation of an outline of a
multicast DSCH communication method according to the present
invention.
[0035] FIG. 4 is an operating sequence diagram of the method of
multicast DSCH communication of FIG. 3.
[0036] FIG. 5 is a view showing an embodiment of a wireless network
control device 303 according to the present invention.
[0037] FIG. 6 is a view showing a practical example of a multicast
setting table 502.
[0038] FIG. 7 is a view showing a practical example of a DSCH
setting table 503.
[0039] FIG. 8 is a view showing what sort of information is set in
the multicast setting table 502.
[0040] FIG. 9 is a view showing what sort of information is set in
the DSCH setting table 503.
[0041] FIG. 10 is a view showing the correspondence of system state
with a specific example.
[0042] FIG. 11 is a view showing the processing sequence from
start-up of the system up to commencement of multicast
communication.
[0043] FIG. 12 is a view showing a specific example of a method of
signaling.
[0044] FIG. 13 is a view showing the processing flow during DSCH
transmission in a wireless network control device 303, in
particular a DSCH processing section 500 and macro diversity
processing section 505.
[0045] FIG. 14 is a view showing the processing flow during DSCH
reception in a mobile.
[0046] FIG. 15 is a view given in explanation of the operation when
a control frame is received from a base station 304.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0047] FIG. 3 is a view given in explanation of an outline of a
multicast DSCH communication method according to the present
invention. FIG. 4 is an operating sequence diagram of the multicast
DSCH communication method according to FIG. 3.
[0048] As described in FIG. 1, the reason why data can only be
received by a single mobile for a single transmission slot is that
a mobile ID is present in the DSCH frame.
[0049] Consequently, according to the present invention, as shown
in FIG. 3B, identification information (multicast ID) for multicast
is stored in the mobile ID storage area 306-2 of the DSCH frame 306
comprising the user data storage area 306-1 and mobile identifier
ID storage area 306-2.
[0050] In this way, it is possible to arrange that a single DSCH
frame 306 can be simultaneously received by a plurality of mobiles
300 to 302. FIG. 3A shows how a DSCH frame 306 using the aforesaid
multicast ID is simultaneously received after reception of
signaling data on their respective DPCHs by a plurality of mobiles
300 to 302.
[0051] The sequence during multicast communication using the DSCH
described in FIG. 3 will be further described using FIG. 4. When
the wireless network control device 303 receives user data from the
core network 100 (not shown in FIG. 3) (step S11), it determines
whether this user data is to be multicast or not; if this data is
not to be multicast, it performs unicast processing in accordance
with the sequence described in FIG. 2.
[0052] If the user data received from the core network 100 is to be
multicast, the wireless network control device 303 generates the
DSCH frame 306 of FIG. 3B (processing step P11) from the
information that was already set as the user data in question.
[0053] After this, the transmission timing of the DSCH frame 306 is
determined (processing step P12). At this point, the multicast ID
is stored in the multicast ID storage region 306-2 described in
FIG. 3 in the DSCH frame 306.
[0054] Next, based on the information relating to multicasting that
is set therein, the wireless network control device 303 selects
mobiles 300 to 302 in respective of which multicasting is to be
performed (processing step P13) and determines (processing step
P14) the transmission timing of the signaling frame and the
generation of the signaling data for each mobile that is the
subject of this multicasting.
[0055] The respective signaling data are transmitted (step S12) to
all the mobiles 300 to 302 that are the subject of multicasting
through the base stations 304, with the aforesaid signaling
transmission timing. When the mobiles receive this signaling, they
recognize the presence of the DSCH frame that is to be received on
PDSCH and commence preparations for reception of this DCSH frame
(processing steps P14-1 to P14-3).
[0056] After this, the wireless network control device 303
transmits the DSCH frame through the base stations of 304 to the
mobiles 300 to 302 with the DSCH frame transmission timing (step
S13).
[0057] After the mobiles have all received the DSCH frame 306
transmitted as described above, they check the mobile identifier ID
in the respectively received data (processing step P15) and, if the
identifier ID agrees with the multicast ID, continue processing of
this received data (processing step P16). If the ID is not a
multicast ID, in the processing step P6 in the sequence of FIG. 2,
the mobiles compare the ID with their own IDs, respectively and, if
they agree, perform the subsequent data processing. Also, if the ID
in the received data and their own ID do not agree, they discard
the DSCH frame 306 (processing step P7).
[0058] An embodiment of a wireless network control device 303 that
executes this processing in a sequence in accordance with the
present invention as described above will now be described.
[0059] FIG. 5 shows an embodiment of a wireless network control
device 303 according to the present invention.
[0060] The wireless network control device 303 comprises a DSCH
processing section 500, macro diversity processing section 505,
main control section 507 and circuit terminating section 506; the
respective functional sections are connected by an internal bus
501.
[0061] The macro diversity processing section 505 is a functional
section for implementing macro diversity, which is a characteristic
technique in mobile communication. In macro diversity, a plurality
of channels are set up between a given node and a given mobile and
identical data are copied and transmitted to all of the plurality
of channels by the transmitting end. This is employed because
communication quality such as during handover is improved by
selecting at the receiving end the data of highest quality, of the
identical data received on the plurality of channels.
[0062] Specifically, the macro diversity processing section 505
chiefly performs the following two processes.
[0063] (1) The data destined for a given mobile received from the
core network 100 is copied to as many channels as are set up on the
mobile in question, and transmission is performed to the mobile on
all these set channels.
[0064] (2) The respective qualities of the data received on the
plurality of channels from a given mobile are evaluated and the
data that afford the best quality are selected and transmitted to
the core network 100.
[0065] The circuit terminating section 506 has the function of
terminating all circuits such as on the side of the core network
100 or on the side of the base stations 304 and of using the
channel to transmit data to a processing block in a suitable device
or another node.
[0066] Apart from setting the information of the various functional
blocks within the device, the main control section 507 has the
function of exchanging control information with other nodes.
[0067] The DSCH processing section 500 comprises a DSCH frame
processing section 504 that performs therein DSCH frame generation
and transmission timing adjustment etc, a multicast setting table
502 that stores information relating to multicasting using DSCH,
and a DSCH setting table 503 that stores information for ordinary
DSCH communication.
[0068] The control information received from the main control
section 507 etc is set and stored in the multicast setting table
502 and/or the DSCH setting table 503. This information that has
thus been set and stored is referenced during for example frame
generation processing or transmission timing determination by the
DSCH frame processing section 504.
[0069] It should be noted that, although, in the embodiment of FIG.
5, the DSCH processing section 500 and the macro diversity
processing section 505 were constituted as separate functional
blocks, this DSCH processing section 500 and macro diversity
processing section 505 could be substantially constituted by a
single functional block.
[0070] FIG. 6 shows a practical example of a multicast setting
table 502. The layout of the multicast setting table 502 is that a
single row shows the setting information of a single multicast
group; this setting information comprises (a) a multicast channel
identifier ID, (b) a DSCH identifier ID, (c) the number of mobiles
participating in this multicast group and (d) the identifier IDs of
these mobiles.
[0071] The details of these respective items of setting information
are described below.
[0072] (a) "Multicast Channel Identifier ID"
[0073] This is the identifier of the multicast data distribution
channel that is set up between the wireless network control device
303 and the core network 100. Although, in this case, it was
assumed that a single multicast channel was always mapped onto a
single DSCH, depending on the layout of the table, it would be
possible to map a single multicast channel onto a plurality of
DSCHs.
[0074] (b) "DSCH Identifier ID"
[0075] This is the identifier that is applied to a DSCH. In this
case also, it is assumed that a single multicast channel is mapped
onto a single DSCH, but, depending on the layout of the table, it
would be possible to map a plurality of multicast channels onto a
single DSCH.
[0076] (c) "Number of Mobiles"
[0077] This indicates the number of mobiles participating in a
multicast group in the DSCH indicated by the DSCH identifier
ID.
[0078] (d) "Mobile Identifier IDs"
[0079] This is a list, having the same number of entries as the
number of mobiles, of the IDs that distinguish the mobiles that
participate in the multicast group.
[0080] FIG. 7 shows a practical example of the DSCH setting table
503. One row of the layout of the DSCH setting table 503 indicates
the setting information relating to a single DSCH; this setting
information comprises: (a) the identifier ID of the dedicated
channel, (b) a DSCH identifier ID, (c) the identifier IDs of the
mobiles corresponding to the identifier ID of the dedicated
channel, and (d) the timing offsets in the signal transmission that
is set up in respect of the mobiles.
[0081] The details of the respective items of setting information
are described below.
[0082] (a) "Identifier ID of the Dedicated Channel"
[0083] This is the identifier of the channel that is uniquely
allocated to the respective mobiles and that is set up between the
wireless network control device 303 and the core network 100. A
single dedicated channel is always mapped onto a single DSCH.
[0084] (b) "DSCH Identifier ID"
[0085] This is the identifier that is applied to the DSCH. A single
dedicated channel is mapped to a single DSCH.
[0086] (c) "Mobile Identifier IDs"
[0087] These are the identifier IDs of the mobiles to which the
dedicated channel is allocated.
(d) "Timing Offset"
[0088] This expresses the amount of offset from the reference
timing in the wireless network control device; transmission is
effected to the mobiles with a timing that is adjusted by the
amount of this offset from this reference timing.
[0089] FIG. 8 and FIG. 9 are views indicating what information is
set in the multicast setting table 502 and the DSCH setting table
503, respectively, corresponding to the specific example of system
condition shown in FIG. 10.
[0090] FIG. 10 shows only the wireless network control device 304;
the base stations 304 are not shown. In this specific example,
three DSCHs, #0 to #2 are set up; the multicast channels MC_CH #0
and #1 and the dedicated channels CH #0 to #2 are accommodated on
the DSCH #0; the multicast channel MC_CH #2 and the dedicated
channels CH #3 to #6 are accommodated on the DSCH #1; and the
dedicated channels CH #7 to #8 are accommodated on the DSCH #2.
[0091] Furthermore, the mobiles #0 to #2 perform communication
through the DSCH #0, the mobiles #0 and #2 are mobiles
participating in multicasting, while the mobile #1 is a mobile that
does not participate in multicasting.
[0092] Also, the mobiles #3 to #5 perform communication through the
DSCH #1 and, of these, the mobiles #3 to #5 are mobiles
participating in multicasting while the mobile #6 is a mobile that
does not participate in multicasting. Further, the mobiles #7, #8
perform communication through the DSCH #2, but these mobiles do not
participate in multicasting.
[0093] In regard to the condition of FIG. 10, the multicast setting
table 502 of FIG. 8 has registered therein (a) which multicast
channels are (b) accommodated on which DSCH and (c) the number of
multicast participant mobiles and (d) the identifier IDs of the
participant mobiles.
[0094] In contrast, the DSCH setting table 503 of FIG. 9 has
registered therein (a) of the dedicated channel IDs, (b) the
subject DSCH identifier IDs that are accommodated therein, and (c)
the corresponding mobile identifier IDs.
[0095] FIG. 11 is a view showing the processing sequence from
start-up of the system up to commencement of multicast
communication.
[0096] When the mobile network i.e. the wireless network control
device 303 and the base stations 304 are started up, various
settings are performed (processing step P21) in accordance with a
predetermined procedure, between these nodes. At this point,
setting of the DSCHs employed in the present invention is also
performed (processing step P22).
[0097] When DSCH setting is completed, next, setting of the data
channels for multicasting between the core network 100 and the
wireless network control device 303 is performed (processing step
P23). Although not shown in FIG. 11, it is assumed that the data
channel for multicasting is connected for example to a data
distribution server within the core network 100 (processing step
P24).
[0098] After set-up of the data channel for multicasting has been
completed, the multicasting setting table 502 within the wireless
network device is updated (processing step P24) in accordance with
the mapping information of the data channels for multicasting that
have been set up and the DSCHs.
[0099] After this, communication of the multicast data from for
example the data distribution server is commenced (step S21). At
this stage, there need not necessarily be any mobile that receives
the multicast data. Alternatively, it is also possible to stop
transmission of the multicast data and to issue the data
transmission commencement request to the server at a time-point
where the mobiles that are to receive the multicast data are
registered.
[0100] After this, when call connection of a particular mobile is
effected (processing step P25), and when, by a prescribed
procedure, a changeover decision is made (processing step P26) to
use DSCH, the wireless network control device adds this mobile to
the DSCH setting table 503 (processing step P27).
[0101] After this, instructions to change over to the DSCH are
transmitted to the mobile 300 in question via the base station 304
(step S22).
[0102] When the mobile 300 receives the instructions to change over
to DSCH, it extracts and sets the parameters for DSCH reception
that are contained in the changeover instruction signal (processing
step P28).
[0103] In addition, a decision is made as to whether or not the
mobile 300 in question is to participate in the multicast
transmission to which DSCH is being applied (processing step P29)
and the mobile 300 in question returns (step S23) to the wireless
network control device through the base station a response message
of completion of DSCH changeover, including the result of this
decision.
[0104] Regarding this decision as to whether or not the mobile 300
is to participate in multicast communication, the methods may be
considered of setting the result of this decision beforehand by the
user in the mobile or of setting the result of this decision in the
network.
[0105] When the wireless network control device 303 receives from
the mobile 300 the DSCH changeover response, if this contains a
request to participate in multicasting, it updates the multicast
setting table 502 therein to add the mobile in question (processing
step P30).
[0106] It should be noted that, if, as the method whereby it is
decided whether or not the aforesaid mobile is to participate in
multicast communication, the method is adopted of setting the
result of this decision in the network, authentication processing
may be performed in the network 100 in the event of reception of a
DSCH changeover response from the mobile, if the mobile is to
participate in the multicast communication, processing may be
performed to add the mobile to the multicast setting table 502.
[0107] After the mobile has been added to the multicast setting
table 502, data is distributed (step S24) from the server or the
like. This distribution data is assembled into DSCH frames in the
DSCH processing section 500 in the wireless network control device
303 and its transmission timing is determined (processing step
P31). After this, signaling in respect of the added mobile (step
S25) and transmission of the DSCH frame (step 26) are
performed.
[0108] For its part, after the mobile has received the signaling
that has been transmitted thereto by the wireless network control
device 303, DSCH reception processing (processing step P32) is
initiated. DSCH frame reception processing (processing step P33) is
performed as described with reference to FIG. 2 (processing steps
P6 and P7) and FIG. 4 (processing steps P15, P16).
[0109] FIG. 12 shows a specific example of a method of signaling.
Signaling must be transmitted to each mobile, so channels for
signaling transmission must be set up allocated in units of the
number of mobiles.
[0110] In 3GPP, as the channels for signaling, two methods are laid
down, namely, a method employing a DCH and a method of setting up a
new channel (signaling bearer) for signaling. Referring to FIG. 12,
a description will now be given as to how signaling is actually
transmitted within the wireless network control device 303 in the
above two cases.
[0111] As described above, since signaling is generated and
transmitted when data is transmitted on the DSCH, the opportunity
for signaling transmission is created by the DSCH processing
section 500.
[0112] This will be described with reference to the following four
cases.
[0113] [Case A]
[0114] The case A shown in FIG. 12A is a case in which signaling is
transmitted with DCH. In accordance with the embodiment described
in FIG. 5, the DCH is terminated by the macro diversity processing
section 505, so in the event of signaling transmission the DSCH
processing section 500 must output a signaling transmission
instruction to the macro diversity processing section 505.
[0115] At this juncture, the macro diversity processing section 505
must be able to identify in respect of which mobile (DCH) signaling
is being transmitted, so the DSCH processing section 500 must give
instructions for signaling transmission to the macro diversity
processing section 505 and hand over the identifier ID of the
mobile that is the subject of this transmission. At this juncture,
in order for the transmission instruction and mobile identifier ID
to be exchanged between the DSCH processing section 500 and the
macro diversity processing section 505, the method of FIG. 5 of
employing an internal bus or the method of providing a dedicated
control path for signal exchange may be considered.
[0116] The macro diversity processing section 505 generates
signaling data from the signaling transmission instruction and
mobile identifier ID received from the DSCH processing section 500
and transmits this signaling data on the corresponding DCH.
Although not shown in FIG. 5, the macro diversity processing
section 505 is internally provided with mapping table means of the
mobile identifier ID and DCH.
[0117] [Case B]
[0118] Case B, shown in FIG. 12B, is also a case in which signaling
is transmitted with DCH. Unlike the case of FIG. 12A, it has a
characteristic feature in regard to the method whereby generation
and transmission of the signaling data are performed by the DSCH
processing section 500 and mapping of the signaling data onto the
DCH is performed by the circuit terminating section 506.
[0119] The DSCH processing section 500 performs transmission of
signaling data to the circuit terminating section 506 using the
same channel ID as the channel of the DCH where the macro diversity
processing section 505 terminates. The channel ID whereby signaling
transmission was performed by the DSCH processing section 500 is
the same as the ID of the DCH corresponding to the mobile that is
to receive the signaling, so the signaling data is merged with the
DCH in the circuit terminating section 506 before being transmitted
to the corresponding mobile through the base station 304.
[0120] It should be noted that, in this case, the DSCH processing
section 500 must simultaneously identify the channel ID of the DCH
corresponding to the mobile that is registered. This can be
achieved by storing as additional information in the DSCH setting
table 503 shown in FIG. 7.
[0121] [Case C]
[0122] In case C shown in FIG. 12C, a channel for signaling
(signaling bearer) is newly set up between the DSCH processing
section 500 and base station 304. This is an example in which
signaling data is transmitted using this channel. In this case, the
signaling data that is generated in the DSCH processing section 500
is transmitted by the signaling bearer at which the DSCH processing
section 500 terminates, without modification.
[0123] [Case D]
[0124] In the case D shown in FIG. 12D, a channel for signaling
(signaling bearer) is newly set up between the macro diversity
processing section 505 and the base station 304; this is an example
of the case where signaling data is transmitted using this channel.
This case also is the same as case A.
[0125] FIG. 13 is a view showing the processing flow during DSCH
transmission in the wireless network control device 303, in
particular in the DSCH processing section 500 and the macro
diversity processing section 505. In this case, case A of FIG. 12A
is employed as the signaling method.
[0126] When the DSCH processing section 500 receives data from the
core network 100 (processing step P40, Yes), the channel ID of the
received data is extracted (processing step P41). The DSCH
processing section 500 checks for the existence of the channel ID
extracted in the processing step P41 in the multicast setting table
502 (processing step P42) by referencing this multicast setting
table 502.
[0127] If the channel ID extracted in the processing step P41 is
present in the multicast setting table 502 (processing step P42,
Yes), the DSCH processing section 500 extracts the DSCH-ID and all
of the mobile IDs belonging to the DSCH from the multicast setting
table 502 (processing step P44).
[0128] Next, if not even one mobile ID is present in the multicast
setting table 502 (processing step P45, No), nor in the DSCH
setting table 503 (processing step P43, No), the data is discarded
(processing step P46).
[0129] If one or more mobile ID is present in the multicast setting
table 502 (processing step P45, Yes) the DSCH processing section
500 applies the data received in processing step P1 to the
multicast ID to generate the DSCH frame (processing step P47).
[0130] On the other hand, if, in processing step P42, the channel
ID extracted in processing step P41 is not present in the multicast
setting table 502 (processing step P42, No), the DSCH processing
section 500 checks to ascertain whether or not the extracted
channel ID is present in the DSCH setting table 503 (processing
step P48).
[0131] If, in processing step P48, the extracted channel ID is not
present in the DSCH setting table 503, the DSCH processing section
500 discards the data received in the processing step P40
(processing step P49).
[0132] If, in the processing step P49, the extracted channel ID is
present in the DSCH setting table 503 (processing step P48, Yes),
the DSCH processing section 500 extracts the DSCH-ID and mobile ID
from the DSCH setting table 503 (processing step P50). After this,
the extracted mobile ID is applied to the data received in the
processing step P1 and the DSCH frame is generated (processing step
P51).
[0133] Next, after the DSCH frame has been generated in the
processing steps P47, P51, the DSCH processing section 500
determines the transmission timing of the DSCH frame that has been
generated (processing step P52) and acquires the timing offset of
the mobile corresponding to this DSCH from the DSCH setting table
503 (processing step P53).
[0134] In this way, the signaling data transmission timing is
calculated (processing step P54) from the DSCH frame transmission
timing and the timing offset of the mobile.
[0135] After this the DSCH processing section 500 reports the
mobile ID and the signaling transmission instruction to the macro
diversity processing section 505 (processing step P55) in
accordance with the signaling timing determined in processing step
P54.
[0136] The macro diversity processing section 505 generates a
signaling frame using the mobile ID and the signaling transmission
instruction that are handed over from the DSCH processing section
500, and transmits this signaling frame on the corresponding DCH
(processing step P56).
[0137] The processing of the aforesaid steps P52 to P56 is executed
a number of times equal to the number of mobiles. After this, the
DSCH processing section 500 transmits (processing step P57) the
DSCH frame generated in the processing step P47 or in the
processing step P51 on the DSCH in accordance with the DSCH frame
transmission timing that was determined in the processing step
P52.
[0138] FIG. 14 is a view showing the processing flow during DSCH
reception by a mobile. In FIG. 14, it is assumed that the dedicated
channels (DCH, DPCH) are already set up by a prescribed procedure
at the mobile.
[0139] When the mobile receives signaling on the DPCH (processing
step P60, Yes)), the DSCH reception preparation is commenced
(processing step P61) and the DSCH frame on the PDSCH is received
(processing step P62).
[0140] After this, an error check of the DSCH frame is performed
(processing step P63). If any abnormality in the data is found, the
received DSCH frame is discarded (processing step P64).
[0141] If the received DSCH frame is normal (processing step P63,
Yes), the identifier ID in the DSCH frame is checked (processing
step P65) and if this identifier ID is a multicast ID (processing
step P66, Yes), data processing as multicast data is performed
(processing step P67).
[0142] On the other hand, if, in processing step P66, it is found
that the identifier ID is not a multicast ID, the identifier ID in
the DSCH frame is compared with the mobile's own identifier ID
(processing step P68) and if it is not found to agree with the
mobile's own identifier ID (processing step P68, No), the received
DSCH frame is discarded (processing step P64).
[0143] If the identifier ID agrees with the mobile's own identifier
ID (processing step P68, Yes), ordinary unicast processing is
performed (processing step P67).
[0144] FIG. 15 describes the operation when a control frame is
received from the base station 304. In 3GPP, various control frames
are defined between the wireless network control device 303 and
base station 304. One of these is a control frame called the timing
adjustment control frame. This is employed to adjust the channel
timing that is set between the wireless network control device and
the base station.
[0145] The timing adjustment control frame is used to store and
transmit the difference with respect to the appropriate reception
timing from the base station 304 to the wireless network control
device 303, in cases where the data that was transmitted by the
wireless network 100 is not received with the appropriate timing at
the base station 304. Also, the timing adjustment control frame is
returned using a channel where the transmission timing is
abnormal.
[0146] When the wireless network control device 303 receives a
timing adjustment control frame, it adjusts the transmission timing
within the wireless network control device 303 by the amount of the
timing to be adjusted that is stored in the frame relating to the
received channel and subsequently performs data transmission with
this timing.
[0147] The details of timing adjustment are set out in 3GPP
TS25.402.
[0148] In a data communication system using DSCH, the signaling
data is transmitted to the mobile immediately prior to transmission
of the DSCH frame, but, as mentioned above, the transmission timing
of the signaling data is based on the transmission timing of the
dedicated channel (DCH, DPCH).
[0149] Consequently, if any abnormality were to be generated in the
transmission timing in the dedicated channel during transmission on
the ordinary dedicated channel, in regard to this dedicated
channel, in the event of an incoming transmission of this timing
adjustment control frame it would not only be necessary to adjust
the transmission timing of this dedicated channel, but it would
also be necessary to adjust the timing offset of each mobile stored
in the DSCH setting table 503 in the DSCH processing section
500.
[0150] Accordingly, as described above, when a timing adjustment
control frame is generated on a dedicated channel, the method is
specified of reporting the control information (in this case, the
timing adjustment value) also to the DSCH processing section 500.
It should be noted that the following method can likewise be
applied to other control frames associated with the dedicated
channel.
[0151] FIG. 15A to FIG. 15C show three patterns, namely, case A,
case B and case C as methods for reporting control information on
reception of a timing adjustment control frame to the DSCH
processing section 500. These three patterns will be described
below.
[0152] [Case A]
[0153] In Case A shown in FIG. 15A, the timing adjustment control
frame that is transmitted on the DCH is terminated by the macro
diversity control section 505, and an adjustment value in respect
of the DCH is extracted from the control frame.
[0154] The macro diversity processing section 505 performs timing
adjustment of the DCH in question within its own processing
section, using the aforesaid adjustment value. The macro diversity
processing section 505 reports this adjustment value and the mobile
ID to the DSCH processing section 500. The DSCH processing section
500 is thereby able to adjust the timing offset amount
corresponding to the mobile in question in the DSCH setting table
503, using the adjustment value and the mobile ID.
[0155] [Case B]
[0156] In case B shown in FIG. 15B, the circuit terminating section
506 copies all of the uplink data that is transmitted on the
dedicated channel terminated by the macro diversity processing
section 505 and transmits this also to the DSCH processing section
500.
[0157] The DSCH processing section 500 is arranged to monitor, all
the time, the uplink data on the dedicated channels that are
received by transmission from the circuit terminating section 506
so as to receive only control data such as timing adjustment frames
and discard ordinary user data. In this way, the DSCH processing
section 500 can also learn the timing adjustment amount on the
dedicated channels.
[0158] [Case C]
[0159] In Case C shown in FIG. 15C, a number of control frame
dedicated channels equal to the number of dedicated channels are
set up between the wireless network control device 303 and the base
stations 304 and control frames are transmitted to the wireless
network control device 303 from the base stations 304 on the
dedicated channels. In this process, respective copied control
frames are transmitted on the dedicated channel in question and the
control frame dedicated channel in question after copying the
control frame within the base station 304.
[0160] Service employing multicast DSCH that is capable of being
implemented by applying the present invention will now be
described.
[0161] As described above, in order for the mobile to receive data
on DSCH, it is essential to receive signaling data on a dedicated
channel (DPCH).
[0162] This means that, in order to receive DSCH, the mobile must
be in call-connected condition rather than in idle condition.
Specifically, a characteristic feature of service using multicast
DSCH is that a service can be provided that is distributed by
multicasting to mobiles that are in connected condition.
[0163] Also, although description thereof has been omitted from the
above, one or several DSCH channels are normally set up for each
area unit and changeover of the DSCH that is being received is
performed when a mobile moves from a given area to another area. In
other words, this may be said to constitute a further
characteristic feature of multicast communication using DSCH in
that different information can be distributed for different
areas.
[0164] Thus the characteristic features of a multicasting service
using DSCH may be summarized as "an area-aware service available
only to mobiles that are in a call-connected condition".
[0165] It should be noted that, since DSCH cannot be received by
mobiles that are not in a call-connected condition, there is no
wasted power consumption due to multicast distribution to mobiles
that are in an idle condition.
[0166] Various examples of such services are described below.
PRACTICAL EXAMPLE 1
Area Information Distribution Service Using Multicast DSCH
[0167] Information relating to this area is constantly distributed
using multicast DSCH, for each area, from for example server means
within the core network, and the mobile receives this area
distribution information by performing call connection.
PRACTICAL EXAMPLE 2
BGM Distribution Service Using Multicast DSCH
[0168] For example music data is constantly transmitted from for
example server means in the core network and this is multicast
within the area using DSCH. When a mobile comes into service by
performing call connection, this distributed music data is received
on the DSCH and reproduced. In this way, it is possible to hear as
BGM this music that is received in the background, while carrying
on a conversation with another party.
[0169] Furthermore, it may be envisioned that a service may be
provided displaying characteristic features for each geographical
region by using different music data for each area. This is of
course not restricted to music data and a similar service could be
provided for all types of audible data.
INDUSTRIAL APPLICABILITY
[0170] There has been an enormous increase in communication rates
and communication quality in recent years due to advances in mobile
communication technology. As a result, service modes have been
diversified and services are being commenced that handle large
quantities of data in the form not merely of voice telephone
service but also of images or video. Currently however, most
services are user request type services and high rate
broadcast/multicast type services such as radio or television are
considered merely as future possibilities.
[0171] Viewed from this aspect, as mentioned above, the current
third-generation mobile communication technology, in particular,
W-CDMA communication networks as specified by 3GPP, are not
considered to provide an optimum method for realizing high rate
multicast services in an efficient manner at the present time. This
must have the effect of impeding the development of communications
services which might be expected to offer high diversity in the
future.
[0172] With the present invention, efficient multicast services can
be implemented simply by revising somewhat the DSCH technology in
3GPP. Also, by exploitation of the highly characteristic technical
feature that "a distributed service allocated in area units can
only be received during call connection", it is envisioned that
various different types of services, which were hitherto difficult
to implement, may be expected to become further developed, leading
to expansion of the mobile communication market.
[0173] Furthermore, it is envisioned that such diversification and
expansion of services will make it possible to change over from a
situation in which communication enterprises obtain profit by
communication charges from users towards a situation in which
communication network charges are obtained from multicast service
providers, thereby making it possible to reduce communication
charges that are currently borne by users, and as a result make it
possible to further expand the market.
* * * * *