Patent Application
20070287440
For the purposes of illustrating the invention, there is shown in the drawings a form which is presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. The features and advantages of the present invention will become apparent from the following description of the invention that refers to the accompanying drawings, in which:
a is a flow chart indicating the steps performed in a piece of UE according to the invention;
b is a flow chart indicating further steps which can be performed by a piece of UE according to the invention; and
The present invention overcomes the above-mentioned problems, by the equipment and methods described and claimed herein.
In accordance with the present invention the MTS is configured to include information indicating the time of change of the active system information. This information is incorporated within data that is received by a piece of user equipment within the MTS.
In light of this feature of the present invention, it is possible for the piece of UE to instantly recognize the time of change of the active system information, and therefore whether it is necessary to read and store the system information being transmitted. For example, if the UE knows that it has not monitored the network for three hours, and the information indicates that the system information was changed an hour ago, the UB recognizes that it must read and store the updated system information.
In order to enable user equipment that has not received or monitored the reference information for some time, to be able to accurately determine if the received reference and system information is in fact newer than the stored information, the present method and equipment incorporates the time of change of the reference and system information with the data.
The current invention relates to equipment and methods of operating the equipment, in which the reference information includes information indicating the time of change of the system information. In such a manner, the UE when receiving the reference information is able to judge whether the value tags differ from one piece of reference information to the next, and should these values be the same, the time of change of the system information is then compared.
A detailed description of operating the method is given below, and with reference to the flow chart of
A piece of user equipment is operating within a MTS, and is in radio communication with the base station in the system. In such a manner, the user equipment is constantly receiving the reference information broadcasts, and is able to maintain the active system configuration data. When the UE stops monitoring or is unable to receive the reference information, none of the reference information data is read (step S1). Upon re-monitoring or being able to receive the reference information again, the UE once again checks the reference information (step 52). The new reference information that is received, has an associated value tag indicating which version of the reference information has been received. In addition to this value tag, the invention provides that the reference information data also includes an information element indicating the time at which the current active system information was changed.
Returning to FIG. la, upon receipt of the reference information (step S3), the UE checks the value tag of the reference information. This value tag is then compared with the stored value within the UE that relates to the last received reference information. If the piece of UE does not contain data relating to previously stored reference information (step S5), that is there is no stored value tag associated with previous reference information, the UE stores the details of the value tag. Additionally, as the UE does not contain the relevant system information, it reads and stores the system information that it has just received, along with the value of the value tag, (step S6). If, however, the UE does contain previously stored reference information system data, the newly received value tag associated with the new reference information is compared with that previously stored (step S7). If the value of the received value tag differs from that of the stored value tag, the UE determines that the received reference information relates to new system information, and therefore reads and stores the system information which is related to the reference information and stores the new value tag (step S6). In this manner, if new system information has been broadcast during the time that the UE was not monitoring or receiving the reference information, the UE is able to get knowledge about the existence of new system information.
In certain circumstances, the UE upon re-monitoring or newly receiving the reference information, will read the associated value tag and find this to be the same as the stored value. In this situation, the piece of UE then compares the information element related to the time of change of the system information received with the reference information (step S8), in order to determine the time of change of the active system information. That is, the UE does not simply accept that because the value tag of the received reference information matches that of the previously stored received reference information value tag, that the system information has not been updated. In this manner, should the reference information value tag change numerous times and repeat itself, the UE is still able to determine whether the stored system information is the same as the received active system information.
More concretely, the UE upon receipt of the reference information and determination that the value tag associated with this received reference information is the same as the stored value, checks the information element related to the time of change of the system information received with the reference information. The UE compares the received value with the value stored within itself (step S9). If the UE does not contain a value associated with the information element related to the time of change, the UE will then assume that it does not have the active system information, and will update the system information related to the received reference information (step S6). Additionally, if the UE does contain information related to the time of change, but this is different from the received value, (step S10) the UE also recognizes that the currently stored system information is not the same as the active system information, and also reads and stores the system information indicated by the current reference information (step S6). If, however, the received time of change value matches the value stored within the UE, the UE recognizes that it currently has the most up to date system information. As such, it simply uses tat which is stored (step S11).
By following the above method, the piece of user equipment is able to determine whether the system information indicated in the reference information is indeed different from that currently stored in the user equipment- Furthermore, the use of the information element related to time of change, denoted as a “time of change information (element)”, removes the possibility of the user equipment mistakenly believing tat te stored system information is the same as the active system information, if the determination is based upon the use of the reference information value tag. The use of the time of change information element is particularly useful, as this can readily be incorporated within current MTS without disruption of te service, and without complete overhaul of the system. That is, current user equipment tat is not adapted for reading the time of change information element, will still function using the received information value tags, whereas user equipment tat is adapted to read the additional information element will operate more efficiently. Clearly, this accurate determination of the active system information assures that each piece of UE has the correct system information configured within itself. Maintaining the accurate system information, has the key advantages of ensuring that the system does not waste time with unnecessary processing, in that the UE does attempt to use an inappropriate radio communication channel. Additionally, the present invention avoids problems with the UE searching for inappropriately configured radio channels, and therefore reduces the power consumption of the system as a whole.
An additional embodiment that can be optionally included in the above method, relates to the system information, and is shown in
In the same manner as the above, each system information packet received, contains time of change data. The UE, upon determination that the system information had changed, according to the steps in figure la, instead of following 86 from
While the above discussion has centred on the reception of the system information and time of change of such at the UE, the BS within such a MTS will now be discussed. The BS continually broadcasts to all of the UEs the system information and the associated reference information. During its normal operation, the BS is continually updating the system information, including the communication channels, repetition rates and the like. This is transmitted over a known channel to the area covered by the BS, indicating the relevant data. In order that users within the BS environment are able to monitor these changes, the reference information data is provided with a value tag, as an indication of the generation of the data. Whenever the broadcast information changes, the BS will change the value tag associated with the reference information and transmit this changed value tag with the new reference information. Each time the system information changes, the value tag transmitted with the reference information changes.
Over several changes of the system information, it is possible for the value tag associated with non-temporally adjacent transmissions to repeat. As such, the ES can further incorporate the time of change of the system information into the reference information being transmitted. Each time the system information changes, the BS changes the value tag and transmits this along with the time of change of the information.
Additionally, as has been discussed above, the system information is often in packet form. That is, the system information is transmitted by the BS in the form of a plurality of packets. It is further possible, in addition to the above time of change being transmitted with the reference information, to associate the time of change of the individual packets of system information. In this way, when an individual packet has been changed, the reference information incorporates the time of change indication, and additionally the packet of system information also includes the time of change. Therefore, the BS monitors the time of change of each individual system information packet, and transmits the relevant time of change of each of these along with the system information packet.
A further embodiment of the MIS and method of operating, relates to sending a time of change element of system information to the UE upon state transition into a state from un-monitoring the broadcasts to monitoring. When a piece of UE state transits, this is associated with signalling messages received at the UE.
In this embodiment the MIS is configured such that the signalling messages received at the UE contains the time of change information element, and the UE is instantly made aware of the time of change of the current system information. The UE then compares the time of change information element received, with that of the value stored. If the time of change of system information received with the signalling messages does not match that of the stored value within the UE, the UE is aware that the system information it currently has is out of date. In this situation, the UE reads the reference information, and reads and stores the system information associated therewith. In this manner, the UE is immediately provided with the relevant system information, and as such can instantly initiate the communication. By undertaking this method, the UB does not waste system resources in attempting to radio communicate along an invalid channel, wastes less power by not attempting to begin radio communication across such an invalid channel, and further is immediately able to communicate within the MIS.
A BS operating within the above disclosed MTS, monitors the UE and notes when this UE transits between states where it is or is not able to monitor or receive the system information. Such changes require that the BS transmit signalling messages which initiate contact and the like. The base station in the current embodiment, in addition to transmitting these signalling messages, is also adapted to transmit the time of change of the system information. Transmitting this time of change information, along with the signalling messages, immediately indicates to the UB the age of the reference information and associated system information.
In each of the above described embodiments, the lime of change information element is sent to the UE using standard communications. That is, the reference information contains the lime of change information element, the standard signalling messages received by the UE on state transition, contain the lime of change information element. It is possible for this information element to be sent in a number of ways. For example, the lime could be based upon the RFC868 time protocoL which is a 32 bit word which indicates the time in seconds since midnight of Jan. 1, 1900. While this is clearly a very accurate way of the UE monitoring the time of change of the system information, it also requires the overhead of sending a 32 bit word over the UMTS. It is preferably possible, therefore, for the additional information element to be a 12 bit word, that indicates the changed lime in minutes since midnight of the current day. Of these two, it is accepted that the second option, that of sending a 12 bit word, requires less system overhead and furthermore provides sufficient accuracy for the UE.
The above description and embodiments are presented by way of example only, and the elements from each embodiment could readily be combined. For example, the embodiment relating to the lime of change being received with signalling messages could also be combined with the individual system information packets containing the lime of change. That is, upon state transition, the UE could be informed of an update of the system information, and then could check which of the packets it is necessary to change.
Additionally, as has been discussed above, the system of the present invention can readily be adopted into existing systems. By way of example, and without any limitation, the above equipment and methods could be combined with the Universal Mobile Telecommunications System, UMTS. For example, within this system, the control and system information is continually broadcast over a broadcast channel, BCH. The UTE is intended to maintain contact with this channel, and thereby obtain the relevant control and system information. The system information packets, are transferred over the BCH as System Information Blocks, SIB. The organisation of these blocks being signalled by the reference information, which is in the form of Master Information Blocks, MIB. These blocks perform the same duties as has been discussed above, and can be considered as analogous. Additionally, the UE within the UMTS maintains a link with the BCH, unless it enters a CELL_DCH state, in which case the UE does not monitor the MIB being transmitted. Upon leaving the CELL_DCH state, the UE receives the BCH and then monitors the MIB value tag to determine the status of the system information, and whether it currently has the most up to date.
As has been described above, the example system according to the UMTS, can suffer from the repetition of the value tag associated with the MIB. In accordance with the present invention, the MIB received at the UE is adapted to include a time of change element which indicates the time of change of the system information. The UE then monitors the MIB, and in the manner described above with relation to
Numerous states exist within the UMTS for the UE to transit into. In particular, when the UE is in the CELL_IJCH state, and not receiving the BCH, upon transition to other states in which it does monitor the BCH, such as the CELL_FACH or CELL_PCH or URA_PCA state, the UE can immediately determine if it has the correct system information. Additionally, the time of change associated with the system information can be received at the UE along with state transition signalling messages.
The BS within the UMIS, provides the MIB and SIB broadcast over the BCH. This BS can readily be adapted to incorporate the information within the MIS, relating to the change of time of the system information. Additionally, it would be further possible to include the time of change of each of the SIBs transmitted over the BCH.
