U.S. patent application number 11/984074 was filed with the patent office on 2008-05-15 for method and apparatus of selecting mbms operating frequency for user equipment in a wireless communications system.
This patent application is currently assigned to Innovative Sonic Limited. Invention is credited to Richard Lee-Chee Kuo.
Application Number | 20080113662 11/984074 |
Document ID | / |
Family ID | 39269349 |
Filed Date | 2008-05-15 |
United States Patent
Application |
20080113662 |
Kind Code |
A1 |
Kuo; Richard Lee-Chee |
May 15, 2008 |
Method and apparatus of selecting MBMS operating frequency for user
equipment in a wireless communications system
Abstract
In order to prevent a user equipment, called UE hereinafter,
from wasting unnecessary radio resources and occurrence of software
failure of the UE, a method of performing an operating frequency
transferring request for the UE in a wireless communications system
includes reporting a request message to request for transferring to
a preferred frequency corresponding to UE interested MBMS services
when the UE operates in the CELL_DCH state and has successfully
selected the preferred frequency as a current operating
frequency.
Inventors: |
Kuo; Richard Lee-Chee;
(Taipei City, TW) |
Correspondence
Address: |
BIRCH, STEWART, KOLASCH & BIRCH, LLP
8110 GATEHOUSE ROAD, SUITE 100 EAST
FALLS CHURCH
VA
22315
US
|
Assignee: |
Innovative Sonic Limited
Tortola
VG
|
Family ID: |
39269349 |
Appl. No.: |
11/984074 |
Filed: |
November 13, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60865607 |
Nov 13, 2006 |
|
|
|
Current U.S.
Class: |
455/418 ;
455/550.1 |
Current CPC
Class: |
H04W 36/22 20130101;
H04W 72/08 20130101; H04W 36/0007 20180801; H04W 72/005
20130101 |
Class at
Publication: |
455/418 ;
455/550.1 |
International
Class: |
H04M 3/00 20060101
H04M003/00; H04M 1/00 20060101 H04M001/00 |
Claims
1. A method for a user equipment, called UE hereinafter, of a
wireless communications system performing an operating frequency
transfer request comprising: reporting a request message to request
transfer to a preferred frequency corresponding to multimedia
broadcast multicast services, called MBMS services hereinafter, the
UE is interested in when the UE operates in a CELL_DCH state and
has successfully selected the preferred frequency as a current
operating frequency.
2. The method of claim 1 further comprising: not reporting the
request message when the UE has not successfully selected a
preferred frequency corresponding to the UE interested MBMS
services as a current operating frequency.
3. The method of claim 1, wherein the request message is a message
named "MBMS MODIFICATION REQUEST message".
4. The method of claim 1, wherein the wireless communications
system is a third generation wireless communications system.
5. A communications device for properly performing an operating
frequency transfer request in a wireless communications system to
prevent from wasting unnecessary radio resources, the
communications device comprising: a control circuit for realizing
functions of the communications device; a processor installed in
the control circuit, for executing a program code to command the
control circuit; and a memory installed in the control circuit and
coupled to the processor for storing the program code; wherein the
program code comprises: reporting a request message to request for
transfer to a preferred frequency of a multimedia broadcast
multicast service, called MBMS service hereinafter, when the
communications device operates in a CELL_DCH state and has
successfully selected the preferred frequency as a current
operating frequency.
6. The communications device of claim 5, wherein the program code
further comprises: not reporting the request message when the
communications device has not successfully selected a preferred
frequency of the MBMS service as a current operating frequency.
7. The communications device of claim 5, wherein the request
message is a message named "MBMS MODIFICATION REQUEST message".
8. The communications device of claim 5, wherein the wireless
communications system is a third generation wireless communications
system.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/865,607, filed on Nov. 13, 2006 and entitled
"Method and Apparatus for MBMS Frequency Selection in a Wireless
Communications System", the contents of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method and apparatus for
a user equipment selecting an operating frequency related to
multimedia broadcast multicast services, called MBMS services, in a
wireless communications system, and more particularly, to a method
and apparatus for a user equipment for properly performing an
operating frequency transfer request in a wireless communications
system to prevent the user equipment from wasting unnecessary radio
resources and occurrence of software failure of the user
equipment.
[0004] 2. Description of the Prior Art
[0005] The third generation (3G) mobile telecommunications system
has adopted a Wideband Code Division Multiple Access (WCDMA)
wireless air interface access method for a cellular network. WCDMA
provides high frequency spectrum utilization, universal coverage,
and high quality, high-speed multimedia data transmission. The
WCDMA method also meets all kinds of QoS requirements
simultaneously, providing diverse, flexible, two-way transmission
services and better communication quality to reduce transmission
interruption rates. To enhance multimedia functions in the 3G
mobile telecommunications system, a protocol specification
developed by the 3rd Generation Partnership Project (3GPP) provides
Multimedia Broadcast Multicast Service (MBMS). MBMS is a
point-to-multipoint bearer service and is established on an
existing network architecture of the Universal Mobile
Telecommunications System (UMTS), utilizing Internet Protocol (IP)
packets as a medium. Thus, MBMS allows a single source entity to
transmit data to multiple user equipments (UEs) simultaneously.
[0006] According to the protocol specification developed by the
3GPP, MBMS offers two delivery modes: MBMS Broadcast delivery mode
and MBMS Multicast delivery mode. When interested in a specific
MBMS service, the UE needs to order the MBMS service from a
Broadcast Multicast Service Center (BM-SC) by establishing a
service agreement including specific service provision phases.
These two delivery modes have different service provision phases.
The service provision phase of MBMS Broadcast delivery mode
includes Service announcement, Session Start, MBMS notification,
Data Transfer and Session Stop. The service provision phase of MBMS
Multicast delivery mode includes Subscription, Service
announcement, Joining, Session Start, MBMS notification, Data
Transfer, Session Stop and Leaving. For realizing customized
services, Joining and Leaving sessions utilized in MBMS Multicast
delivery mode enable the BM-SC to execute authorization and payment
recording for the UEs at the Joining session. The service provision
phases mentioned above are well known in the art, and will not be
described in detail.
[0007] On the other hand, from the standpoint of radio resource
control (RRC), all logical data communication exchange channels, be
they for providing data transmission exchange to the UE or for
providing RRC layer control signal transmission exchange, are
defined in the context of a Radio Bearer (RB). In the UE end, the
RB comprises one unidirectional, or a pair of, uplink/downlink
logic data transmission exchange channels. In the network end, the
RB comprises one unidirectional, or a pair of, uplink/downlink
logic data transmission exchange channels. For example, a UMTS
Terrestrial Radio Access Network (UTRAN) transmits MBMS
configuration to the UE by establishing RBs, and the UE stops
receiving MBMS service by releasing the RBs. Besides, according to
the RRC protocol specification provided by the 3GPP, an RRC state
of the UE can be a disconnection mode or an RRC connection mode.
The disconnection mode includes Idle mode, and the RRC connection
mode includes CELL_PCH, URA_PCH, CELL_FACH and CELL_DCH states.
[0008] When providing the MBMS service, the UTRAN may obtain the
number of the UEs ordering the MBMS service via a counting
procedure, and can adopt either one of the following two
transmission modes: point-to-point (p-t-p) transmission and
point-to-multipoint (p-t-m) transmission. The UTRAN utilizes the
p-t-m transmission to transfer data if the Broadcast mode is
selected. On the contrary, if the Multicast mode is selected, the
UTRAN utilizes either the p-t-p transmission or the p-t-m
transmission to transfer data according to the number of the UEs.
In the p-t-p transmission, transmission between the UEs and the
UTRAN utilizes a dedicated channel, and thereby the Node-B
establishes one dedicated channel for one UE to transmit data and
configuration. Compared with the p-t-p transmission, the p-t-m
transmission allows a core network (CN) to provide the data and the
configuration for multiple UEs in the same cell simultaneously.
[0009] In the protocol specification developed by the 3GPP, three
logical channels are defined to transmit corresponding MBMS
information: MBMS point-to-multipoint Control Channel (MCCH), MBMS
point-to-multipoint Traffic Channel (MTCH), and MBMS
point-to-multipoint Scheduling Channel (MSCH). MCCH is utilized to
transmit a corresponding MBMS configuration, including MBMS
Neighboring Cell Information, MBMS Radio Bearer Information, MBMS
Service Information, and other information. MTCH is responsible for
transferring service data to the UEs. MSCH is used for notifying
the UEs with scheduling information of MBMS services. With MSCH,
the UEs are allowed to execute reception only when data begins to
be transferred, without needing to keep a receiving state on
throughout the whole service process.
[0010] Generally speaking, the UTRAN includes two or more carrier
frequencies for providing a variety of services for UEs, and the
UEs are appropriately distributed on these carrier frequencies. On
the other hand, for the UE end, when the MBMS service the UE is
interested in, or the state of the joined MBMS service, changes,
the UE can perform a frequency selection procedure for following
service reception operations. According to the meeting document
R2-063613 of the 3GPP (3GPP TSG-RAN WG2 Meeting #56), when the UE
receives an information element (IE) "MBMS Preferred frequency
information" or an IE "MBMS PL Service Restriction Information," or
when the preferred MBMS service changes, the UE shall perform an
MBMS frequency selection procedure for transferring a current
operating frequency to a preferred frequency corresponding with an
MBMS service prioritized by upper layers, so as to execute
reception of the concerned MBMS service. The IE "MBMS Preferred
frequency information" is included in a message named "MBMS
MODIFIED SERVICES INFORMATION", and is utilized for notifying the
UE of the preferred frequency layer corresponding to the concerned
MBMS services. The IE "MBMS PL Service Restriction Information" can
be sent to the UE through a Radio Bearer Control message, a CELL
UPDATE CONFIRM message or an MBMS GENERAL INFORMATION message, and
is utilized for notifying the UE that the UTRAN will not provide
any new non-MBMS services on the preferred frequency layer, which
means that the preferred frequency layer is currently congested. In
other words, if the IE "MBMS PL Service Restriction Information" is
not included in the MBMS GENERAL INFORMATION message for the
preferred frequency layer, there are still free radio resources
available on the preferred frequency layer where the UTRAN can also
provide the non-MBMS services.
[0011] Additionally, according to the protocol specification
developed by the 3GPP, the above Radio Bearer Control message and
the CELL UPDATE CONFIRM message are sent on a dedicated control
channel (DCCH) for a dedicated UE, and the MBMS GENERAL INFORMATION
message is sent on MCCH, which is broadcasted for all UEs in a
cell. The Radio Bearer Control message can be a RADIO BEARER
RECONFIGURATION message, a RADIO BEARER SETUP message, a RADIO
BEARER RELEASE message, a TRANSPORT CHANNEL RECONFIGURATION message
or a PHYSICAL CHANNEL RECONFIGURATION message, which are well known
by those skilled in the art, and thus not narrated herein.
[0012] As the UE operates in different RRC states, the behavior of
performing the MBMS frequency selection procedure is also
different, and the following is aimed at a situation in which the
UE operates in the CELL_DCH state. Initially, if there exists one
or more preferred frequencies for services included in a variable
MBMS_ACTIVATED_SERVICES, which is stored in the UE, and the latest
received CELL UPDATE CONFIRM message or Radio Bearer Control
message did not include the IE "MBMS PL Service Restriction
Information", which is sent by the UTRAN on DCCH, the UE can
proceed to following frequency selection.
[0013] Then, the UE selects a preferred frequency corresponding to
the MBMS service(s) prioritized by upper layers as the operating
frequency, for which the IE "MBMS PL Service Restriction
Information" is not included in the MBMS GENERAL INFORMATION
message. Finally, the UE can request that the UTRAN be moved to the
preferred frequency by means of the MBMS MODIFICATION REQUEST
message.
[0014] In some cases, such as when the IE "MBMS PL Service
Restriction Information" is included in the MBMS GENERAL
INFORMATION message for each preferred frequency corresponding with
the MBMS service which the UE is interested in, the UE will fail on
selecting the operating frequency. Thus, there is no need for the
UE to request to be moved to another frequency in this situation.
Requesting to be moved to another frequency in this situation is
only a waste of radio resources. Besides, a software error may
occur when trying to send the MBMS MODIFICATION REQUEST message
because there is no preferred frequency selected. However,
according to the above-mentioned meeting document, when the UE
operates in the CELL_DCH state and performs the MBMS frequency
selection procedure, the UE has to report the MBMS MODIFICATION
REQUEST message to the UTRAN no matter whether a preferred
frequency corresponding with the MBMS service which the UE is
interested in has been successfully selected or not.
SUMMARY OF THE INVENTION
[0015] According to the present invention, a method for a user
equipment, called UE hereinafter, of a wireless communications
system performing an operating frequency transfer request comprises
reporting a request message to request for transferring to a
preferred frequency corresponding to multimedia broadcast multicast
services, called MBMS service hereinafter, the UE is interested in
when the UE operates in a CELL_DCH state and has successfully
selected the preferred frequency as a current operating
frequency.
[0016] According to the present invention, a communications device
for properly performing an operating frequency transferring request
in a wireless communications system to prevent from wasting
unnecessary radio resources comprises a control circuit for
realizing functions of the communications device; a processor
installed in the control circuit, for executing a program code to
command the control circuit; and a memory installed in the control
circuit and coupled to the processor for storing the program code.
The program code comprises reporting a request message to request
for transferring to a preferred frequency of a multimedia broadcast
multicast service, called MBMS service hereinafter, when the
communications device operates in a CELL_DCH state and has
successfully selected the preferred frequency as a current
operating frequency.
[0017] These and other objectives of the present invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the preferred
embodiment that is illustrated in the various figures and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a functional block diagram of a communications
device.
[0019] FIG. 2 is a diagram of the program code shown in FIG. 1.
[0020] FIG. 3 is a flowchart diagram of a process according to an
embodiment of the present invention.
DETAILED DESCRIPTION
[0021] Please refer to FIG. 1, which is a functional block diagram
of a communications device 100. For the sake of brevity, FIG. 1
only shows an input device 102, an output device 104, a control
circuit 106, a central processing unit (CPU) 108, a memory 110, a
program code 112, and a transceiver 114 of the communications
device 100. In the communications device 100, the control circuit
106 executes the program code 112 in the memory 110 through the CPU
108, thereby controlling an operation of the communications device
100. The communications device 100 can receive signals input by a
user through the input device 102, such as a keyboard, and can
output images and sounds through the output device 104, such as a
monitor or speakers. The transceiver 114 is used to receive and
transmit wireless signals, delivering received signals to the
control circuit 106, and outputting signals generated by the
control circuit 106 wirelessly. From a perspective of a
communications protocol framework, the transceiver 114 can be seen
as a portion of Layer 1, and the control circuit 106 can be
utilized to realize functions of Layer 2 and Layer 3. Preferably,
the communications device 100 is utilized in a third generation
(3G) mobile communications system.
[0022] Please continue to refer to FIG. 2. FIG. 2 is a diagram of
the program code 112 shown in FIG. 1. The program code 112 includes
an application layer 200, a Layer 3 202, and a Layer 2 206, and is
coupled to a Layer 1 218. The Layer 3 202 includes a radio resource
control (RRC) entity 222, which is used for controlling the Layer 1
218 and the Layer 2 206 and performing peer-to-peer RRC
communication with other communications devices, such as a base
station or a Node-B. In addition, the RRC entity 222 can change an
RRC state of the communications device 100, switching between an
Idle mode, CELL_PCH, URA_PCH, CELL_FACH or CELL_DCH state.
[0023] As for Multimedia Broadcast Multicast Services (MBMS), a
UMTS Terrestrial Radio Access Network (UTRAN) can generate RRC
messages and information elements (IEs) to include MBMS
configuration and then transmit them with a Point-to-Point Radio
Bearer (p-t-p RB) or a Point-to-Multipoint Radio Bearer (p-t-m RB)
to the communications device 100. In the CELL_DCH state, when the
application layer 200 is about to use an MBMS service or the state
of a joined MBMS service changes, the RRC entity 222 performs a
frequency selection procedure for transferring a current operating
frequency to a corresponding carrier frequency to execute following
service reception operations. In this situation, the embodiment of
the present invention provides an operating frequency transfer
request program code 220 to improve an operating frequency transfer
request mechanism when the frequency selection procedure is
executed in the CELL_DCH state, so as to prevent unnecessary waste
of radio resources and software errors. Please refer to FIG. 3,
which illustrates a schematic diagram of a process 30 according to
an embodiment of the present invention. The process 30 is utilized
for a user equipment (UE) of a wireless communications system
performing an operating frequency transfer request, and can be
compiled into the operating frequency transfer request program code
220. The process 30 includes the following steps:
[0024] Step 300: Start.
[0025] Step 302: Report a request message to request transfer to a
preferred frequency corresponding to an MBMS service the UE is
interested in when the UE operates in the CELL_DCH state and has
successfully selected the preferred frequency as a current
operating frequency; and do not report the request message when the
UE has not successfully selected a preferred frequency
corresponding to the MBMS services the UE is interested in as the
current operating frequency.
[0026] Step 304: End.
[0027] According to the process 30, the embodiment of the present
invention reports a request message to the UTRAN for requesting to
be transferred to a preferred frequency corresponding to the MBMS
services the UE is interested in when the UE operates in the
CELL_DCH state and has successfully selected the preferred
frequency as a current operating frequency. Preferably, the process
30 is utilized in an MBMS frequency selection procedure, and the
request message is an MBMS MODIFICATION REQUEST message. Thus, when
the UE performs the MBMS frequency selection procedure in the
CELL_DCH state, the UE will not report the MBMS MODIFICATION
REQUEST message to the UTRAN for the situation where no preferred
frequency corresponding with the UE interested MBMS services has
been selected successfully, so as to save radio resources and
prevent occurrence of software failure of the UE.
[0028] Therefore, compared with the prior art, the embodiment of
the present invention requests the UTRAN to be moved to the
preferred frequency by means of the MBMS MODIFICATION REQUEST
message only if the UE has successfully selected the preferred
frequency corresponding with the MBMS service prioritized by the
application layer 200 as a current operating frequency. In this
case, when there are no preferred frequencies capable of being
selected by the UE, i.e. the IE "MBMS PL Service Restriction
Information" is included in the MBMS GENERAL INFORMATION message
for each preferred frequency corresponding to all MBMS services the
UE is interested in, the embodiment of the present invention need
not report the MBMS MODIFICATION REQUEST message to the UTRAN to
prevent from causing unnecessary waste of radio resources and
software error of the UE.
[0029] As mentioned above, in the prior art, when the UE performs
the MBMS frequency selection procedure in the CELL_DCH state, the
UE has to report the MBMS MODIFICATION REQUEST message to the UTRAN
no matter whether a preferred frequency has been successfully
selected or not. By comparison, the embodiment of the present
invention reports the MBMS MODIFICATION REQUEST message only when
the UE has successfully selected a preferred frequency
corresponding with the MBMS services the UE is interested in as a
current operating frequency. Therefore, the embodiment of the
present invention can prevent the UE from wasting unnecessary radio
resources and occurrence of software failure of the UE.
[0030] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
* * * * *