HK1182261A - Dedicated radio resource control - Google Patents

Description

Dedicated radio resource control

The present application is a divisional application of patent application No.200780045595.0 entitled "dedicated radio resource control" filed on 2009, 10, 2009, japan electrical corporation.

Technical Field

The present invention relates to a method and related apparatus for controlling handover between dedicated radio resources of a mobile radio communications network.

Background

One option for providing data/services via a mobile radio communications network is to provide such data/services via dedicated radio resources, such as corresponding Radio Bearers (RBs).

To enhance the selection and diversity of data/services available to one or more intended recipients, a requirement arises for switching between different dedicated radio resources. However, current mechanisms for providing such improved selection by allowing switching between such dedicated radio resources exhibit disadvantageous limitations and inefficiencies.

As one of many examples, the following discusses the provision of television services over a 3G mobile radio communications network, which is part of a Multimedia Broadcast Multicast Service (MBMS) broadcast.

In the operating environment of such a television service (hereinafter referred to as "mobile TV"), the receiver of the service can only watch one channel at a time. Then, when there is a need to switch from one frequency channel to another, a mechanism is needed that allows switching between dedicated radio resources (on which the respective frequency channel is transmitted).

Although there is a possibility for providing mobile TV over point-to-multipoint broadcast systems via mobile radio communication networks, there is a problem of radio inefficiency compared to the use of point-to-point bearers, which has been identified as part of the 3GPP RAN2 conference on day 28, 8/2006. Although the use of point-to-multipoint broadcasting may provide advantageous characteristics with respect to cell loading, the radio resource efficiency and improved bearers provided by point-to-multipoint systems, as well as the relatively low number of users within a particular cell who need to receive point-to-point MBMS broadcasts, dictate that the efficiency requirements of mobile TV can be easily met practically without restriction by using dedicated radio resources such as those provided by point-to-point systems.

When a recipient of mobile TV services wishes to switch from one channel to another, in case both channels are sent over dedicated RB resources, the current RB must be released before a new RB is established, since two completely separate Radio Resource Control (RRC) messages for these purposes are derived from the 3G Radio Access Network (RAN).

Thus, for example, with reference to the Universal Telecommunications Radio Access Network (UTRAN), the current sequence of operations for switching between frequency channels includes first communicating a request to a User Equipment (UE) to release the current RB using an RB release message, and then requesting the UE to set up an RB associated with the new desired frequency channel using an RB set-up (set-up) message that requires the UE to perform Dedicated Physical Channel (DPCH) synchronization. This synchronization needs to be two times and two responses to the UTRAN (i.e., one for each received message) including the Signaling Radio Bearer (SRB) delay time for each sent response.

When a current point-to-point arrangement is employed to effect switching between dedicated RB channels, the replication of DPCH frame synchronization, the transmission of acknowledgement messages for the new configuration, and the associated SRB delays disadvantageously limit the efficiency currently available for mobile TV.

Although the use of point-to-point bearers improves the efficiency of mobile TV compared to point-to-multipoint broadcasting, such efficiency is not limited as described above.

The present invention seeks to provide a method and apparatus for handover between dedicated radio resources within a mobile radio communications network which exhibits advantages over known methods and apparatus.

In particular, the present invention seeks to improve radio resource efficiency for a dedicated radio resource service (e.g. mobile TV).

Disclosure of Invention

According to an aspect of the present invention there is provided a method of controlling switching between dedicated radio resources of a mobile radio communications network, comprising sending an RRC message to a UE within the network, the RRC message requesting both RB release and RB setup at the UE.

Thus, the present invention advantageously provides a single RRC message for controlling RB release and setup. In this way, much improved, much faster switching between dedicated radio resources (e.g. switching between different channels providing mobile TV) may be experienced at the UE, since the processing time within the UE may be greatly reduced. For example, duplicate DPCH frame synchronization is no longer required and a separate acknowledgement message is sent for the new configuration, as these actions need only be performed once.

As an additional advantage, it is noted that a reduction of the signaling overhead in UTRAN can also be achieved.

Although it is recognized that certain disadvantages in the prior art are discussed in connection with mobile TV services, and that certain advantages and specific details discussed further below relate to such an environment, it should be appreciated that the present invention may be advantageously used in any scenario where a handover between dedicated resources is required, such as handovers occurring in connection with 3GPP Release99, Release6 or Long Term Evolution (LTE) features.

Advantageously, the method further comprises the step of sending an RB reconfiguration complete message from the UE to the network.

Preferably, the aforementioned single message may include RB configurations for two dedicated radio resources.

Alternatively, the aforementioned single message may be arranged to include an existing RB configuration, but which has been updated in view of the characteristics of the dedicated radio resources to which handover is required.

The method may further include implementing at least one of an MBMS service configuration change or a PDCP/RLC configuration change over an existing RB.

In addition, the aforementioned single message may also be arranged to change the multiplexing of the Medium Access Control (MAC) and, if necessary, to reconfigure the transport and physical channels for dedicated radio resources.

In one particular example of the invention, the method involves switching between dedicated radio resources providing MBMS.

In this arrangement the aforementioned single message initiating the reconfiguration represents an update to the MBMS service identity.

As yet another feature, the reconfiguration message allows for updating Packet Data Convergence Protocol (PDCP) and/or updating Radio Link Control (RLC) configuration.

In addition, as described above with particular reference to MBMS transmission, the MAC and physical configuration may be arranged to be reconfigured by a single message.

It will of course be appreciated that the method of the present invention may be implemented as a method for controlling switching between channels of a mobile TV service.

According to another aspect of the present invention there is provided a method of initiating a handover within a UE of a mobile radio communications network between dedicated radio resources, comprising the steps of receiving and processing an RRC message at the UE, the RRC message being arranged to initiate both RB release and RB setup within the UE.

Advantageously, the method further comprises the step of sending an RB reconfiguration complete message from the UE to the network.

Preferably, the single message may include RB configurations for two dedicated radio resources.

Alternatively, the aforementioned single message may be arranged to include an existing RB configuration, but which has been updated in view of the characteristics of the dedicated radio resources to which handover is required.

The method may further include implementing at least one of an MBMS service configuration change or a PDCP/RLC configuration change over an existing RB.

In addition, the aforementioned single message may also be arranged to change the multiplexing of the Medium Access Control (MAC) and, if necessary, to reconfigure the transport and physical channels for dedicated radio resources.

In one particular example of the invention, the method may also involve switching between dedicated radio resources providing MBMS.

In this arrangement the aforementioned single message initiating the reconfiguration represents an update to the MBMS service identity.

As yet another feature, the reconfiguration message allows for updating Packet Data Convergence Protocol (PDCP) and/or updating Radio Link Control (RLC) configuration.

In addition, as described above with particular reference to MBMS transmission, the MAC and physical configuration may be arranged to be reconfigured by a single message.

It will of course be appreciated that the method of the present invention may be implemented as a method for initiating a switch between channels of a mobile TV service.

According to a further aspect of the present invention there is provided a mobile radio communications device arranged to receive dedicated radio resources of a mobile radio communications network and to provide handover therebetween, the device being arranged to receive an RRC message, the RRC message being used to initiate both RB and RB setup within the device.

Advantageously, the apparatus is arranged to send an RB reconfiguration complete message from the UE to the network.

Preferably, a single message required by the present invention may include RB configurations for two dedicated radio resources.

Alternatively, the single message may be arranged to include an existing RB configuration, but which has been updated taking into account the characteristics of the dedicated radio resources to which handover is required.

The mobile radio communications device may be further arranged to allow at least one of an MBMS service configuration change or a PDCP/RLC configuration change to be effected over an existing RB.

In addition, the single message may also be arranged to change the multiplexing of the Medium Access Control (MAC) and, if required, to reconfigure the transport and physical channels for dedicated radio resources.

In one particular example of the invention, the apparatus is arranged for providing handover between dedicated radio resources for MBMS.

In this arrangement the aforementioned single message initiating the reconfiguration represents an update to the MBMS service identity.

As yet another feature, the reconfiguration message allows for updating Packet Data Convergence Protocol (PDCP) and/or updating Radio Link Control (RLC) configuration.

In addition, as described above with particular reference to MBMS transmission, the MAC and physical configuration may be arranged to be reconfigured by a single message.

It will of course be appreciated that the apparatus of the present invention may include functionality for controlling switching between channels of a mobile TV service.

According to a further aspect of the present invention there is provided a network element for use within a mobile radio communications network for controlling switching between dedicated radio resources of the network, the network element being arranged to send an RRC message to a mobile radio communications device within the network, the RRC message serving as a request for both RB release and RB set-up within the mobile radio communications device.

As before, a single message from this element may advantageously include RB configurations for both dedicated radio resources.

Alternatively, the message may be arranged to include an existing RB configuration, but which has been updated taking into account the characteristics of the dedicated radio resources to which handover is required.

Of course, at least one of the MBMS service configuration change or the PDCP/RLC configuration change may be provided through the existing RB.

In addition, the aforementioned single message may also be arranged to change the multiplexing of the Medium Access Control (MAC) and, if necessary, to reconfigure the transport and physical channels for dedicated radio resources.

In one particular example of the invention, the network element is arranged to initiate a handover between dedicated radio resources providing MBMS.

In this arrangement, the message initiating the reconfiguration exhibits an update to the MBMS service identity.

As yet another feature, the reconfiguration message allows for updating Packet Data Convergence Protocol (PDCP) and/or updating Radio Link Control (RLC) configuration. Also, as described above with particular reference to MBMS transmission, the MAC and physical configuration may be arranged to be reconfigured by a single message.

It will of course be appreciated that the network elements of the present invention may be arranged specifically for controlling switching between channels of a mobile TV service.

It will thus be appreciated that the present invention may prove particularly advantageous when a relatively low number of users within a particular cell need to receive MBMS broadcasts. That is, when there are a relatively small number of users within a cell, network operator decisions may be taken to transmit using point-to-point resources, which may be based on a particular threshold level.

Point-to-point resources prove to be advantageously efficient, since point-to-point RB configurations require less signaling than point-to-multipoint RB configurations, since it can be appreciated that point-to-multipoint configurations require four MCCH messages, including modified (Modify) or unmodified (Unmodify), common ptm (common ptm), Current (Current), Neighbor (Neighbor).

In addition, in a scenario where a UE arrives within a cell and no other UEs are receiving service at that time, the network can easily establish a point-to-point RB configuration for that particular UE, as compared to a point-to-multipoint configuration where the UE will not receive service until the start of the next modification period.

In addition, point-to-point transmission is more reliable than point-to-multipoint and therefore does not require the network operator to configure neighboring cells for selective/soft combining in an attempt to improve service reception. However, for point-to-point configurations, RLC technology mode may be used.

Drawings

The invention is further described, by way of example only, with reference to the accompanying drawings, in which:

fig. 1 is a timing diagram illustrating switching between channels of a mobile TV service according to the current art; and

fig. 2 is a similar timing diagram illustrating switching between different channels of a mobile TV service according to an embodiment of the present invention.

Detailed Description

Turning first to fig. 1, there is provided a timing diagram 10 illustrating messaging occurring between a UE, for example a mobile radio communications device 12, and a Radio Network Controller (RNC)14 of a 3G network, by which timing diagram 10 the UE12 is arranged to receive one of a plurality of possible channels of a mobile TV service.

In fact, at 16, the diagram shows that the UE12 is currently receiving "channel 1" of two possible mobile TV channels delivered through point-to-point communication.

When the UE12 may need to receive an alternate channel, such as "channel 2," also available on the network, the RNC14 provides the MBMS modified services information signal 18 to the UE12 to confirm whether channel 2 is available if needed. If it is determined at the UE12 that channel 2 is preferred over channel 1, the UE is arranged to send an MBMS modification request signal 20 to the RNC14 indicating that channel 2 is actually preferred and that channel 1 can be released.

It should be appreciated that the request signal 20 is generated in response to user interaction in the upper layers of the application within the UE12, and that channel 2 is identified as being preferred over channel 1 since the user can only view one channel at a time.

It will be appreciated from the discussion of fig. 2 that follows below that the initial signaling and control described above may be common to both the current art and the illustrated embodiment of the present invention.

With continued reference to fig. 1, however, upon receipt of the signal 20, the RNC14 issues a radio bearer release signal 22 relating to the channel 1 configuration in accordance with the current art.

Upon receiving the radio bearer release signal 22 and completing the physical release of the RB, the UE12 issues a radio bearer release complete message 24 to the RNC 14.

During this operation, the RRC performs the actions specified in TS25.3318.2.2.3, i.e., determines the beginning of the DPCH frame and adjusts the radio link accordingly, and sends a response back to the UTRAN the most recent (100+ TTI) ms after completing the reception of the last TTI of the bearer triggered UTRAN → UE message. When the "target state" is CELL _ DCH, the UE response message sent from the physical layer may be additionally delayed by the value of the delay IE "SRB delay".

After the radio bearer release complete message 24 the RNC14 issues a further message 26 asking for radio bearer setup for channel 2 configuration.

Once the setup procedure is completed within the UE12, the UE12 issues a radio bearer setup complete message 28, which message 28 is passed to the RNC 14.

Also as part of the radio bearer setup complete procedure, the RRC is arranged to perform the actions specified in TS25.3318.2.2.3 and discussed above in connection with the radio bearer release complete message 24, which actions will be described below.

Thus, within UTRAN, the current behavior consists of the following: the UE is requested to release the current RB using a radio bearer release message and then requested to set up a new RB using a radio bearer setup message. This requires the UE to perform DPCH synchronization twice (as mentioned in TS25.3318.2.2.3) and two responses to the UTRAN (one for each received message) are sent, including an SRB (signaling radio bearer) delay time for each response.

Once the release of channel 1 and subsequent set up of channel 2 is complete, the UE12 continues its mobile TV reception service, but now in conjunction with channel 2, as indicated at 30.

The advantages of distinguishing the features of the present invention will be appreciated from the following comparison with figure 2.

As mentioned above, the illustrated embodiment of the present invention also involves signaling between the UE12 and the RNC14, and such signaling occurs after the UE12 receives the frequency channel 1(16) of the mobile TV service.

The UE12 also receives the MBMS modification service information signal 32 indicating that channel 2 service is available (if needed), and after deciding that channel 2 is preferred, the UE12 issues an MBMS modification request 34 to the RNC14 indicating this preference.

Thus, it should be appreciated that the UE12 initially receives channel 1 via the point-to-point RB, and then the UE12 is informed by the point-to-point RB that a new channel (channel 2) is available, as illustrated by the MBMS modified services information message 32. As before, as a result of the request to the upper application layer of RRC, the user indicates that UE12 prefers to receive channel 2 instead of channel 1 and that the preference is signaled to the UTRAN using MBMS modification request procedure 34.

Also with regard to UTRAN, the proposed behavior consists of: the UE is requested to release the current RB and to set up a new RB using only a radio bearer reconfiguration message including (i) both radio bearer configurations, or (ii) an existing radio bearer configuration updated in view of the new MBMS service.

Referring specifically to the latter half of the operation as shown in fig. 2, upon determining at the RNC14 that a service needs to be switched to channel 2, the RNC14 is configured to issue a single radio bearer reconfiguration message 36. As described above, this single message may either allow the channel 1 configuration to be released and the channel 2 configuration to be set up, or may allow the channel 1 configuration to be updated to adopt the configuration associated with channel 2. In this configuration, the MBMS service identification (or PDCP/RRC information) may be adaptively changed with respect to the characteristics of channel 2.

Upon receipt of the single radio bearer reconfiguration message 36 at the UE12, the reconfiguration request is processed within the UE12 and a radio bearer reconfiguration complete message 38 is passed to the RNC 14.

Also, the RRC may perform the actions specified in TS25.3318.2.2.3, i.e., determine the beginning of the DPCH frame and adjust the radio link accordingly. Then, it sends a response back to the UTRAN the last (100+ TTI) ms after completing the reception of the last TTI of the bearer triggered UTRAN → UE message. When the target state is CELL _ DCH, the UE response message sent from the physical layer may be additionally delayed by the value of the delay IE "SRB.

The UE12 then continues to receive mobile TV service as before, but now receives channel 2, as indicated by step 30 of fig. 2.

It will be appreciated by comparing fig. 1 and 2 that the switch from channel 1 to channel 2 can be achieved in a much faster and more efficient manner than previously by MBMS point-to-point services, which in particular serve to meet the efficiency requirements of mobile TV services.

Since embodiments of the present invention require reconfiguration of the radio bearer, it is proposed that the current radio bearer reconfiguration message can be changed to allow the following configuration scheme using a single reconfiguration message.

First, existing point-to-point radio bearer configurations are able to support new MBMS channels (services), i.e. only the relevant MBMS service identity is updated (e.g. "MBMS service/session identity" information of IE "RB reconfiguration information"). Second, the PDCP and/or RLC configuration is updated (e.g., all information of IE "RB reconfiguration info"). Third, the MAC and physical configuration are updated (e.g., IEs "MBMS RB list to release" and "MBMS RB list to setup").

Upon receiving the Information Element (IE) in the message, the RRC performs a legacy procedure to reconfigure an existing RB or release a current RB and set up a new RB.

The modifications to the RRC recommendation are outlined below with particular reference to the various sections of the 3GPP TS25.331 (radio resource control (RRC); protocol specification, Release 6) requirements):

8.6.4 radio bearer information element

[…]

8.6.4.5RB reconfiguration information

If the IE "RB reconfiguration information" is included, the UE should apply the following actions to the radio bearer identified with the value of the IE "RB identity". The UE shall:

[…]

1> if ie(s) "MBMS service identity" and (additionally) "MBMS session identity" exist:

2> for MBMS radio bearers, consider replacing the current identity/session with a given MBMS service identity/session.

8.6.9 MBMS-specific information element

[…]

8.6.9.10 Release of the MBMS RB List

If the IE ("to release MBMS RB list") is included, the UE should:

1> the IE "RB info release" action is performed according to subclause 10.3.4.19, which action is applied to the list of radio bearers to be released.

8.6.9.11 an MBMS RB list is to be set up

If the IE "to set up MBMS RB list" is included, the UE should:

1> the IE "RB info setup" action is performed according to subclause 10.3.4.20, which action is applied to the list of radio bearers to be set up.

As a further indication of a proposed modification to the RRC recommendation, section 10.2 "radio resource control message" should be modified to include a new section 10.2.2 "radio bearer configuration" with an associated table in which the "needed" column entry includes

10.2.2 radio bearer configuration.

This message is sent from the UTRAN to reconfigure parameters related to a change in QoS or related to a change in (prioritized) MBMS service. The process may also change the multiplexing of the MAC, reconfiguring transport channels and physical channels. This message is also used to perform handover from GERAN Iu mode to UTRAN.

RLC-SAP: AM or UM or by GERAN Iu mode

Logical channel: DCCH or Transmission over GERAN Iu mode

The direction is as follows: UTRAN → UE

In addition, regarding the radio bearer information element, it is proposed that section 10.3.4 be modified as follows to include the MBMS service identification information element shown.

Radio bearer information element

[…]

Reconfiguration RB information

This application is based on and claims priority from GB patent application No.0624647.4 filed on 11.12.2006, the disclosure of which is incorporated herein by reference in its entirety.

Claims (4)

1. A method of controlling handover between dedicated radio resources of a mobile radio communications network, the method comprising:

transmitting a radio resource control, RRC, message to a mobile radio communications device within the network, the RRC message serving to initiate both radio bearer RB release and radio bearer RB setup by the mobile radio communications device to switch between dedicated radio resources providing a first multimedia broadcast multicast service, MBMS, and dedicated radio resources providing a second multimedia broadcast multicast service, MBMS, in response to the RRC message.

2. A method of initiating handover within a mobile radio communications device of a mobile radio communications network between dedicated radio resources, the method comprising:

receiving and processing at the mobile radio communications device a radio resource control, RRC, message from a network element, the RRC message serving to initiate both radio bearer RB release and radio bearer RB setup within the mobile radio communications device to switch between dedicated radio resources providing a first multimedia broadcast multicast service, MBMS, and dedicated radio resources providing a second multimedia broadcast multicast service, MBMS, in response to the RRC message.

3. A mobile radio communications device arranged to receive dedicated radio resources of a mobile radio communications network and to provide handover therebetween, the mobile radio communications device comprising:

means for receiving and processing a radio resource control, RRC, message from a network element, the RRC message being used to initiate both a radio bearer RB release and a radio bearer RB setup within the mobile radio communications device to switch between dedicated radio resources providing a first multimedia broadcast multicast service, MBMS, and dedicated radio resources providing a second multimedia broadcast multicast service, MBMS, in response to the RRC message.

4. A network element for use in a mobile radio communications network for controlling handover between dedicated radio resources of the network, the network element comprising:

means for sending a radio resource control, RRC, message to a mobile radio communications device within the network, the RRC message being used to initiate both a radio bearer RB release and a radio bearer RB set-up within the mobile radio communications device to switch between dedicated radio resources providing a first multimedia broadcast multicast service, MBMS, and dedicated radio resources providing a second multimedia broadcast multicast service, MBMS, in response to the RRC message.