Title of Invention

METHOD TO NOTIFY BROADCAST SYSTEM INFORMATION CHANGE IN RADIO COMMUNICATION NETWORKS

Abstract

In a mobile telecommunication system with a plurality of cells and active user equipments, where the network broadcast system information to assist user equipments in accessing the system and there is a need to indicate any change in the broadcast system information, and user equipments need new and updated information to access the network resources. The method comprises, in the network, if there is any change in the broadcast system information, the change indication happens by the use of a common paging message or a dedicated paging message, whereby the user equipments are indicated to read the latest system information and update the information stored.

Full Text

FIELD OF THE INVENTION The present invention, in general, relates to communication networks that involve dynamic radio resource control and dynamic access control assistance to equipments/devices trying to access the network. With the assistance from broadcasted network control information/parameters user equipments/devices can access the network resources. More particularly, the present invention relates to broadcast system information change notification in radio communication networks. BACKGROUND OF THE INVENTION In mobile telecommunications system, the communication between the network and the mobile station is carried out by the use of various protocols. The network system acts as the controller by handling a number of user equipment (UEs) which can be a mobile station or any other equipment. For the communication to be successful over a radio link, certain set of agreed and understandable parameters needs to be transacted between the network and the UE(s). The network system being the controller indicates these parameters that will be required by the UE(s) in order to access the system resources or communicate with the network. This agreed information or the set of parameters which is required to be understood both by the UE and the network in order to successfully establish a context with each other is grouped together and called as the system information. This information needs to be broadcast to all the UE(s) (as shown in Fig. 1) as it should be possible for all the UE(s) to atleast be able to read and check if a communication is possible or not. The system information is broadcast at Cell levels in the mobile telecommunication systems. The Ceil is the least granular geographical area controlled by NodeB. NodeB is the immediate point of contact to all the UE(s). The broadcast system information helps the UE(s) to configure its layers as required by the network. The use of this information is always required for the UE(s) to perform a set of agreed/allowed procedures. The system information is broadcast in the form of blocks called System Information Blocks (referred as 'SIB' hereafter). These blocks are continuously broadcast with different repetition periods on a particular frequency band. Each SIB has a fixed repetition period in time. Based on the criticality of the information required by the UE(s), the size of the information and the purpose, the repetition periods are arranged with the most critical one having the shortest repetition period. The SIB with the shortest time interval between instances is called the MIB. This block has the scheduling information, which is the time frequency resource indicator, of other SIBs that carry specific information. By reading the MIB, other SIBs can be read by the UE(s) by using the scheduling information. Each SIB has two identifiers, to be used for different purposes. First one is the SIB number which is the primary identifier that identifies what that block is. The second iderrtifier is the SIB Value-Tag which is used to indicate the current version of the SIB. Whenever there is a change in the content of any SIB the value-tag of SIB gets incremented consequently leading to increment of the value-tag of the MIB also. Simply stating, whenever a value-tag of a SIB is changed, it affects in the change of the value-tag of the MIB (or the SIB that carries the scheduling information of that changed SIB). This we call it as the value-tag technique. In case of a UMTS system, the terminology used are the MIB, Scheduling Blocks (SBs) and SIBs. Scheduling Blocks are the extensions of the MIB which again carry the scheduling information of the SIBs. Since MIB is the only SIB that carries the scheduling information of all the other SIBs, UMTS systems have a single level of control represented by the MIB. In case of an LTE system, the terminologies used are the MIB and the Scheduling Units (SUs). SUs are again blocks of information just like SIBs with different repetition periods. Here the MIB carries the scheduling information of the first SU alone called the SU-1. The scheduling information of the rest of the SUs is carried in the SU-1 So there exist two levels of control, one represented by the MIB and the next by the SU-1. So there is a two level of hierarchy in the broadcast system information. We use the term SIB to represent both SU in LTE and SIB in UMTS hereafter. Please refer to the figures 1,2 and 6 under the diagrams section for a better understanding of the paragraphs below. Whenever there is a change in any of the System Information Blocks, the change has to be communicated to all the UE(s) under the ambit of the network. UE(s) in idle mode are notified by using the Paging Type 1 message (as shown in Fig.2). UE(s) in connected mode are notified by using a dedicated message called the System Information change indication message (as shown in Fig 3). The details of this procedure is well explained in 3GPP TS 25.331 v5.9.0 Sections 8.1.1.7, 10.2.49. The procedure uses the value-tag technique to indicate a change in the broadcast system information which comprisesthe MIB value tag along with the time from which the change is effective. Suppose there are four broadcast system information blocks that are arranged in hierarchy, say MIB, SIB1, SIB2, SIB3. The timing relationships between them are as depicted in Fig.7. o MIB→ Block that contains the scheduling information of SIBs 1, 2 and 3. This block repeats itself every 40ms, say. Note: Since this block provides the scheduling information of the other blocks and also have a higher repetition period compared to others, we call this a control block. So MIB forms the first level of control. Suppose, SIB1 has scheduling information of say, SIB 5, 6, 7(if they exist), then SIB1 forms the second level of control. o SIB1 → This block carries some information and repeats every 80ms o SIB2 → This block has a repetition period of 120ms o SIB3 → This block has a repetition period of 160ms Scenario: Suppose information in SIB3 changes, methods as known in the prior art would indicate the change either by o Paging (For UEs in Idle mode) -> comprising new value tag and the time from which the change is effective (as shown in Fig. 2) (or) o System Information Change Indication message (For UEs in Connected mode) -^ comprising' new value tag and time from which the change is effective ( as shown in Fig. 3) Suppose, system information change indication is received by the UE (ex: a mobile device) at point P (T=85ms) (as shown in Fig 7), the mobile device has to wait for 35ms to read MIB (point X in Fig 7) and then o Check for the changes in the value-tags of SIBs 1,2 and 3, o Read the scheduling information of SIBs whose contents have changed o Wait for 120ms to read the SIB and update its database. So in all, it takes 85+120, i.e., 205ms to read the changes and update itself. Existing arts deal with the updation of SIB information in a UE in a telecommunication system, however, the solutions lack promptness in reacting to the changes in the SIBs leading to delay in updation of said information in the UE, As 3G network is constantly evolving giving its way to more advanced version in near future such as LTE (or 4G) which would include multiple levels of controls, this delay would get accumulated at every level making the situation worse. Further the necessity to read unchanged information of the control blocks is an overhead in case of networks where changes in broadcast system information are frequent. SUMMARY OF THE INVENTION It is thus an object of the invention to develop a method and an apparatus implementing the method so as to solve the above-mentioned drawbacks. The object of the invention is achieved by a method and system which are characterized by what is stated in the independent claims. Preferred embodiments of the invention are set forth in the dependent claims. In the method proposed by the present invention, the network transmits the system information at the time of indicating the change to the UB. The network incorporates the system information in the paging indication message itself. The paging indication message includes information such as preamble, SIB number, SIB value tag, and scheduling information. The preamble is a key indicator that indicate the level at which the changes have taken place. Therefore, the UE can update the system information without a need to read an MIB to find out the change and thereby reducing the delay to update the change. Accordingly the invention describes method to notify broadcast system information change in a radio communication networks such as UMTS wherein the change indication happens by the use of a common paging message or a dedicated paging message, whereby the user equipments are indicated to read the system information and update the said information. The method further comprises of directly updating value-tags of higher levels of control SIBs based on the system information change notification. Change indication at various control levels are indicated using a preamble. The preamble is appropriately modified to handle scheduling information carried at the subsequent levels. If multiple SIBS at one level have changed then the scheduling information of the previous higher level is sent to optimize the modify indication message. If multiple SIBS at different control levels have changed, then scheduling information of the highest level SIB change is indicated. The change indication message is composed of absolute or relative scheduling information of the changed system information. These and other objects, features and advantages of the present invention will become more apparent from the ensuing detailed description of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1 - depicts the broadcasting of current system information by the Radio Access Network across the Cell Figure 2 depicts the sending of system information change indication (via Paging type 1 message) to all the UEs in IDLE state. Figure 3 depicts the sending of system information change indication message to all the UEs in CONNECTED state. Figure 4 depicts UMTS protocol stack Figure 5 depicts LTE protocol stack Figure 6 depicts System Information Change indication method as proposed in the in related prior art Figure 7 depicts the system information change indication scenario currently followed, explaining the disadvantage in the currently followed method DETAILED DESCRIPTION OF THE INVENTION The preferred embodiments of the present invention will now be explained with reference to the accompanying drawings. It should be understood however that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. The following description and drawings are not to be construed as limiting the invention and numerous specific details are described to provide a thorough understanding of the present invention, as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. However in certain instances, well-known or conventional details are not described in order not to unnecessarily obscure the present invention in detail. The proposed method involves the usage of a preamble representing each level of control, that case solve the two problems of ü Reading unchanged broadcast system information ü Waiting for a considerable period to update changes Consider a parameter that is dynamically changing based on the network load. This is dynamic and so the System Information Block that carries this parameter need frequent updating by the mobile device. The method proposed involves the following: ü The information element 'BCCH-Modificationlnfo' can have the following contents mentioned in the table below: The 'n+1' bit preamble can be used to indicate to indicate the number of levels of control. As mentioned in the example above, if there exists only one level of hierarchy of control blocks, carrying scheduling information of subsequent set of blocks, then n will be equal to 2. Suppose there is a change in say SIB3, then the new value tag of SIB3 along with the scheduling information of SIB3 and SIB identifier (SIB number) is received on the paging or change indication message. The preamble is the key indicator that indicates the level at which the changes have taken place. By using the scheduling information the mobile device can read the changes directly and update its database. The updating procedure also involves, incrementing the value-tags of all the preceding control blocks. This is because the value-tag technique involves the incrementing of the value tag of all the top level control blocks in the hierarchy. Where m is the number of bits required to represent the total number of System information blocks. For example: if there are 8 SIBs, then we need 3 bits (number of SIBs = 2'"). The preamble bits indicate the level at which the changes have taken place. The following table explains the method for the above example. In all the three cases, the difference in the preamble indicates changes at different levels along with the multiplicity in the changes. « Explanation: In the above case, changes have taken place in only on SIB. So the scheduling information and the value tag of this SIB are directly sent in the paging or system information change indication message. This information is present in the IE BCCH-Modificationlnfo. Explanation: In the above case, changes have taken place in only in the MIB. So the scheduling information and the value tag of this MIB are directly sent in the paging or system information change indication message. Explanation: This is the special case, wherein many SIBs have changed. So the scheduling information and the value tag of the MIB are directly sent in the paging or system information change indication message. This is because, MIB is the just preceding control block that carries the scheduling information of the SIBs that have changed. Simply stating, if there are changes in multiple SIBs in the same level, it is efficient for the network to send the value-tag of the control block that carries the scheduling information of the changed SIBs. The updating of all the preceding control blocks involve finding out the number of changes that have taken place. Suppose 'n' SIBs at the same level have changed, the value-tag of the control block of these SIBs could have either got incremented either by 'n' or 'less than n'. Based on the value that has changed the value of the preceding control blocks of this control block needs to be updated by the mobile device on its database. EFFECTS / ADVANTAGES OF THE INVENTION ? Extending this makes to 'n' levels optimizes the method of notification of system information change. ? More the levels of control, better is the optimization ? More the number of blocks/units in a particular level that is prone to changes, better is the optimization ? More frequently there are changes in the system information, better will be optimization of notification when this method is used. ? When there is a change in the a particular information that does not necessitate the reading of the complete set of broadcast system information, this method works efficiently ? When there are multiple changes of multiple units at any level, the value tag and sib-number of the preceding level is sent. This enables in reading the changed broadcast system information blocks using the value-tag mismatch technique ? When there are more levels of control and more number of units/blocks within the same level of control that is prone to changes, this method is efficient ? This also allows for dynamically changing the broadcast system information without providing for activation times. It will also be obvious to those skilled in the art that other control methods and apparatuses can be derived from the combinations of the various methods and apparatuses of the present invention as taught by the description and the accompanying drawings and these shall also be considered within the scope of the present invention. Further, description of such combinations and variations is therefore omitted above. It should also be noted that the host for storing the applications include but not limited to a microchip, microprocessor, handheld communication device, computer, rendering device or a multi function device. Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are possible and are apparent to those skilled in the art- Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart there from. GLOSSARY OF TERMS AND DEFINITIONS THEREOF WE CLAIM: 1. A method to notify broadcast system information change to a UE in a radio communication network wherein said UE receives a system information change notification message comprising an Information Element from said network, where said Information Element having a preamble representing each level of control, a SIB number, a SIB Value Tag and associated Scheduling Information, whereby said preamble indicates the level at which said change has taken place thereby said UE directly updating its database by reading said Scheduling Information. 2. The method according to claim 1 wherein, said system information change notification message is receivable by said UE when a signaling connection is active between said UE and said network. 3. The method according to claim 2 wherein, said system information change notification message is receivable by said UE through a System Information Change Indication message. 4. The method according to claim 1 wherein, said system information change notification message is receivable by said UE when a signaling connection is not active between said UE and said network. 5. The method according to claim 4 wherein, said system information change notification message is receivable by said UE through a paging message. 6. The method according to claim 1 wherein, said Information Element is Broadcast Control Channel Modification Information. 7. The method according to claim 1 wherein, said number of levels of control is represented by 'n+1' bits in said preamble. 8. The method according to claim 1, wherein said preamble is appropriately modified to handle said scheduling information carried at said subsequent levels. 9. The method according to claim 1 further comprising of directly updating value- tags of higher levels of control SIBs based on said system information change notification message. 10. The method according to claim 1 wherein, said scheduling information of a higher control level is sent to optimize said system information change notification message when SIBs at a single control level subsequent to said higher control level have changed. 11. The method according to claim 1 wherein, said scheduling information of the highest control level SIB change is sent to optimize the system information change notification message when multiple SIBs at a plurality of control levels subsequent to said highest control level have changed. 12. The method according to claim 1 wherein, said system information change notification message is composed of absolute or relative scheduling information of the changed system information. 13. A method to notify broadcast system information change in a radio communication network substantially described particularly with reference to the accompanying drawings.

Documents:

2541-CHE-2007 AMENDED PAGES OF SPECIFICATION 12-09-2013.pdf

2541-CHE-2007 AMENDED CLAIMS 12-09-2013.pdf

2541-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 12-09-2013.pdf

2541-CHE-2007 FORM-13 12-09-2013.pdf

2541-CHE-2007 POWER OF ATTORNEY 12-09-2013.pdf

2541-CHE-2007 FORM-13 13-12-2013.pdf

2541-CHE-2007 FORM-13 16-12-2013.pdf

2541-che-2007-abstract.pdf

2541-che-2007-claims.pdf

2541-che-2007-correspondnece-others.pdf

2541-che-2007-description(complete).pdf

2541-che-2007-drawings.pdf

2541-che-2007-form 1.pdf