CLIAMS:claims ,TagSPECI:
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003

PROVISIONAL SPECIFICATION
(See section 10, rule 13)

“A method and system for transmission, by a base station, of system information to at least one mobile terminal”

Tejas Networks Limited
Plot No. 25, JP Software Park,
Electronics City, Phase-1, Hosur Road
Bangalore - 560 100, Karnataka, India

The following specification particularly describes the invention.

Field of the Invention

The present invention relates to communication field, more specifically, to a method for transmitting system information.

Background of the Invention

The Third Generation Partnership Project (3GPP) has initiated the Long Term Evolution (LTE) program to bring new technology, new network architecture, new configurations and new applications and services to wireless networks in order to provide improved spectral efficiency and faster user experiences. Figure 1 shows an overview of an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E- UTRAN) 100 in accordance with the prior art. As shown in Figure 1, E-UTRAN 100 includes three eNodeBs (eNBs) 102, however, any number of eNBs may be included in E-UTRAN 100. The eNBs 102 are interconnected by an X2 interface 108. The eNBs 102 are also connected by an S1 interface 106 to the Evolved Packet Core (EPC) 104 that includes a Mobility Management Entity (MME) 112 and a Serving Gateway (S-GW) 110.

System information (SI) is information that is broadcast within a cell and provides information about configurations and parameters that are common to at least some of the wireless transmit receive units (WTRUs) in the cell. System information messages may include parameters such as network identification, neighbouring cells, channel availability and power control requirements etc. In the existing system message design, depending on different repetition periods, the SIB is included in different SI. The SI is a Radio Resource Control (RRC) message that carries at least one SIB. The SI is sent on the radio frame periodically. Each SIB includes a series of relevant SI parameters.
In the long-term evolution (LTE) system, system information may be divided into main information block (MIB), system information block 1 (SIB1) and ordinary system information (SI).
Wherein the MIB is transmitted in a broadcasting channel with a transmitting cycle of 40 milliseconds, and the MIB is repeatedly transmitted in sub-frame #0 of each wireless frame within its transmitting cycle. SIB1 is transmitted in a downlink shared channel with a scheduling cycle of 80 milliseconds, and SIB1 is repeatedly transmitted in sub-frame #5 (sub-frame number starts from 0) of a wireless frame satisfying SFN % 2=0 (wherein SFN is the system frame name) within its scheduling cycle; and other system parameters are included in other system information blocks (SIB). The contents of system parameters comprise service cell information, cell reselection information and adjacent cell information of intra-frequency, inter-frequency and other radio access technologies (RAT) etc.
The above SIBs are mapped into different System Information (SI) messages to realize scheduling, that is, the SIBs are defined according to their contents, wherein SI serves as a scheduling unit, the scheduling information of these SIs are included in SIB1, and the scheduling information specifically comprises a transmitting window w, a scheduling cycle n and so on. The order that the SI appears in the scheduling information of SIB1 is called as scheduling order n, the transmitting windows of all SIs are the same, but the scheduling cycles may be different. The transmitting window of the SI is a limited time range, within which the SIBs mapped into the same SI are repeatedly transmitted, but it is not determined in which sub-frame the transmission is conducted, that is, a terminal needs to try to receive and decode the SI in each sub-frame within the transmitting window. In the LTE system, to simplify the scheduling process, the relation between the scheduling cycles N of all SIs is in general that one is simply multiple of another, and they all have even number of frames. For example, the scheduling cycle N may be 8 frames, 16 frames and so on, which makes a certain SFN to become a common multiple of some SIs, i.e. satisfying SFN % N=0.To facilitate description, the above SI is called SI group on the SFN in the following description.
The scheduling rule of SI is described as follows: supposing that the size of the transmitting window is w sub-frames, the scheduling cycle of a certain SI is N and the scheduling order thereof is n, then the starting wireless frame and sub-frame of the transmitting window of the system information may be represented by the following formulae: SFN % N=COUNT+floor(w*(n-1)/10), sub-frame=(w*(n-1)) % 10, wherein COUNT is a constant and may be 0 or 8 for example. If COUNT is larger than or equal to N, then COUNT shall be modified to be COUNT % N. It can be seen that when n=1, sub-frame=0, that is, the transmitting window of SI with n=1 begins from sub-frame #0 of the wireless frame satisfying SFN % N=COUNT. For the SIs with n larger than 1, following the SI with n=1, they shall be continuously transmitted within their respective transmitting windows in sequence. For example, it is assumed that there are 7 SIBs all together, i.e. SIB2, SIB3, SIB4, SIB5, SIB6, SIB7 and SIB8, and these SIBs are mapped into 7 SIs, i.e. SI-1, SI-2, SI-3, SI-4, SI-5, SI-6, and SI-7 , in a one-to-one manner and their scheduling cycles are 160 ms, 320 ms, 640 ms, 640 ms, 1280 ms, 1280 ms and 1280 ms, respectively.
In LTE, for system information window length of 1 millisecond, the number of system information messages that can be transmitted is limited. It is specified in the LTE system that other SIs are not allowed to be transmitted in sub-frame #5 satisfying SFN % 2=0 in order to avoid mixing SIB1 and other SIs on the same sub-frame. Further uplink subframe and special subframe for which special subframe configuration does not support PDSCH transmission and MBSFN subframes block the transfer of system information message.
Thus, there is a need to propose an alternative method to overcome the above mentioned limitation so that transmitting conflict between the SI and SIB1 can be avoided.
Brief description of the drawings

A more detailed understanding may be had from the Detailed Description below, given by way of example in conjunction with drawings appended hereto.
Figure 1 shows an overview of a typical E-UTRAN.
Figure 2 shows an example wireless communication system including a plurality of WTRUs and an eNB according to one embodiment.
Figure 3 is a block diagram of a WTRU and the eNB of Figure 2.
Figure 4 (a) shows an example of SIB 1 having a scheduling information list according to one embodiment of the present invention.
Figure 4 (b) shows an example configuration table and the periodicity of SI messages according to one embodiment of the present invention.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.

Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

Detail description of the Invention
When referred to hereafter, the term "wireless transmit/receive unit (WTRU)" includes, but is not limited to, a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a computer, or any other type of user device capable of operating in a wireless environment. When referred to hereafter, the term "base station" includes, but is not limited to, a Node B, a site controller, an access point (AP), or any other type of interfacing device capable of operating in a wireless environment.
Figure 2 shows a wireless communication system 200 including a plurality of WTRUs 210 and an e Node B (eNB) 220. As shown in Figure 2, the WTRUs 210 are in communication with the eNB 220. Although three WTRUs 210 and one eNB 220 are shown in Figure 2, it should be noted that any combination of wireless and wired devices may be included in the wireless communication system 200.
Figure 3 is a functional block diagram 300 of a WTRU 210 and the eNB 220 of the wireless communication system 200 of Figure 2. As shown in Figure 2, the WTRU 210 is in communication with the eNB 220. The WTRU 210 is configured to receive and process emergency and non-emergency SI messages. In addition to the components that may be found in a typical WTRU, the WTRU 210 includes a processor 315, a receiver 316, a transmitter 317, and an antenna 318. The WTRU 210 may also include a user interface 321, which may include, but is not limited to, an LCD or LED screen, a touch screen, a keyboard, a stylus, or any other typical input/output device. The WTRU 210 may also include memory 319, both volatile and non- volatile as well as interfaces 320 to other WTRU's, such as USB ports, serial ports and the like. The receiver 316 and the transmitter 317 are in communication with the processor 315. The antenna 318 is in communication with both the receiver 316 and the transmitter 317 to facilitate the transmission and reception of wireless data. [0024] In addition to the components that may be found in a typical eNB, the eNB 220 includes a processor 325, a receiver 326, a transmitter 327, and an antenna 328. The receiver 326 and the transmitter 327 are in communication with the processor 325. The antenna 328 is in communication with both the receiver 326 and the transmitter 327 to facilitate the transmission and reception of wireless data. The eNB 220 is configured to transmit and process emergency and non-emergency SI messages.
Figure 4 (a) shows an example of SIB 1 having a scheduling information list according to one embodiment of the present invention. In an embodiment of the present invention, the UE acquires SIB 1 includes a scheduling information list. The SIB 1 includes other system information messages (i.e. SI1, SI2, SI3…etc). Each SI record has data as shown in the scheduling information list. For example SI1 has SIB2 and SIB3 and both the information has to follow a periodicity of 8 i.e. rf8. Based on the information available at the SIB1, all SIs are scheduled as per scheduling information list. As per standard, SIB1 is transmitted repeatedly in sub-frame #5 (sub-frame number starts from 0) of a wireless frame satisfying SFN % 2=0 (wherein SFN is the system frame name) within its scheduling cycle; and other system parameters are included in other system information blocks (SIB). The above mentioned method, determines whether a NULL information element present in any of SI number from the SI message record of the scheduling information list. This NULL information element (SI-Message Mast Count) is added by the base station before transmitted SIB1. Upon determining the NULL information element by UE, the UE adds a value present in the NULL information element to the corresponding SI number to calculate a new SI number. In the table as shown in figure, SI5 has SINumMask[1]. Upon retrieval of SI5, the method has to add a value (in the present case [1]) to the SI number. After SI 5, the method starts decoding SI6 where the method directs to add a value of [1] to the SI number which becomes SI7. The UE jumps to the next SI number by calculating the SI window from the new calculated SI number to process all other SI records thereby facilitating the transfer of number of system information messages to the maximum limit.

Figure 4 (b) shows Table 1 illustrates the example solution for the following configuration – SI-window length = 1ms, TDD Config 0, Special subframe format 1, downlink cyclic prefix – Normal, for this configuration, the subframes to be excluded for downlink transmission are – subframe #5 for all radio frames (SF#5 in SFN#0 and SF#5 in SFN#1), uplink subframes for TDD networks (SF#2, SF#3, SF#4, SF#7, SF#8, SF#9 in SFN#0 and SFN#1). Hence the subframes to be excluded – SFN#0 -- SF#2,SF#3, SF#4, SF#5, SF#7, SF#8, SF#9. This can be achieved by sending SINumMaskCount4 in SF#1 and NULLCount3 in SF#6 in SFN#0. In this case, the SchedulingInfo can be transmitted as shown in figure.

SchedulingInfo[0] ::= SEQUENCE { si-Periodicity rf16 sib-MappingInfo SIB-MappingInfo }

SchedulingInfo[1] ::= SEQUENCE { si-Periodicity rf32 sib-MappingInfo SIB-MappingInfo si-MessageMaskCount 4 }

SchedulingInfo[2] ::= SEQUENCE { si-Periodicity rf64 sib-MappingInfo SIB-MappingInfo si-MessageMaskCount 3 }

SchedulingInfo[3] ::= SEQUENCE { si-Periodicity rf32 sib-MappingInfo SIB-MappingInfo }

SchedulingInfo[4] ::= SEQUENCE { si-Periodicity rf32 sib-MappingInfo SIB-MappingInfo si-MessageMaskCount 4 }

SchedulingInfo[5] ::= SEQUENCE { si-Periodicity rf64 sib-MappingInfo SIB-MappingInfo si-MessageMaskCount 3 }

Examples of several embodiments of the present invention have been described in detail above, with reference to the attached illustrations of specific embodiments. As it is not possible, of course, to describe every conceivable combination of components or techniques, those skilled in the art will appreciate that the present invention can be implemented in other ways than those specifically set forth herein, without departing from essential characteristics of the invention. Note that although terminology from 36PP LTE-Advanced has been used in this disclosure to exemplify the invention, this should not be seen as limiting the scope of the invention to only the aforementioned system. Other wireless systems including or adapted to include multi-layer transmission techniques may also benefit from exploiting the ideas covered within this disclosure. Also note that terminology such as base station and UE should be considered non-limiting as applied to the principles of the invention. In particular, while detailed proposals applicable to the uplink in LTE-Advanced are described here, the described techniques may be applied to the downlink in other contexts.

Abstract
A method and system for transmission, by a base station, of system information to at least one mobile terminal

The present invention provides a method by which System Information messages can be transmitted on discontinuous system information windows of System Information window length 1 millisecond to facilitate the transfer of number of System Information messages to the maximum limit. In one embodiment this is accomplished by acquiring a part of system information by the mobile terminal broadcasted by the base station including SIB 1, calculating valid radio frames and valid sub frames available in a SI window, wherein the calculated frames provides the number of opportunity available in the SI window for scheduling SIs, retrieving SI messages from the received SIB 1 and calculate SI window for each corresponding retrieved SI message and calculating upon acquiring SI-1 (SIB2), valid radio frames and valid sub frames available in the SI window, wherein the calculated valid radio frames and valid sub frames provides the number of opportunity available in the SI window for scheduling the other SI messages in the corresponding SI windows and acquiring other SI messages in the valid radio frames and valid sub frames.