Method and mobile station to perform initial cell search in time slotted systems

A cell search and mobile station technology, applied in the direction of code division multiplexing system, communication between multiple stations, network data management, etc., can solve the problems of lack of frequency correction channel, high cost, etc., and achieve accelerated scanning operation , Accelerate the effect of the initial cell search

CN1615667AInactive Publication Date: 2005-05-11SIEMENS INFORMATION & COMM NEWTWORKS INC
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2005-05-11
Estimated Expiration
Not applicable · inactive patent

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Abstract

A method is disclosed that a Mobile Station MS performs at switch-on to search the most favorable target cell in UMTS systems like the 3GPP CDMA LCP (Low Chip Rate) option at (1.28) Mcps TDD (Time Division Duplex) mode and the equivalent TD-SCDMA (Time Division Synchronous CDMA). Signal at the MS antenna is the surn of different RF downlink frames coming from different carriers in the assigned frequency ranges. A DL synchronization timeslot and a BCCH TS0 codes assigned on cell basis. Following a conventional approach the absence of a common downlink pilot and without prior knowledge of the used frequencies would force the MS, for all the frequencies of the channel raster stored in the SIM card, the correlation of the received frame with all the (32) sYNCs stored in the MS, in order to detect the BSIC of a cell to which associate are performed in two-step scan of the PLMN band without interleaved correlation steps; once a final frequency is selected the respective frame is the only correlated one. At least one frame duration about (5) ms long of the whole (15) MHz bandwidth is acquired, IF converted, A / D converted and the digital set is stored.
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Description

technical field

[0001] The present invention relates to the field of wireless mobile systems, and more precisely, to a method and mobile station (MS) architecture for initial cell search in a time slotted system. Background technique

[0002] To find a cell, an initial cell search is performed by the MS at power-on, from which downlink data can be reliably decoded and which has a high communication probability on the uplink. Due to the marketization of the next new third-generation PLMN (Public Land Mobile Network), this PLMN will add its features to the existing PLMN in a certain period of time, because there are many operating frequency bands and different synchronization requirements, the initial cell search is very important to the MS ( mobile station) will be a very tricky task.

[0003] figure 1 A possible typical radio frequency reduction scenario faced by the mobile station MS1 ​​is shown schematically. The described scenario includes three cells: cell 1 in which ...

Examples

Embodiment Construction

[0057] already discussed figure 1 to 6. Fig. 7 schematically shows, without limitation, a possible narrowband architecture of a known art BTS transmitter. The transmitter includes a BSC (Base Station Controller) interface that forwards relevant protocol messages to as many carrier transmitters as there are planned carriers in the cell. Each carrier transmitter consists of at least the following blocks: baseband processor-TX, QPSK modulator, two identical RRC (Root Raised Cosine, Root Raise Cosine) type TX filters with low pass channel frequency band (1.6MHz) , IF oscillator (digital), summer and RF-TX. The Baseband Processor-TX receives protocol messages and processes them according to the specification. In particular it is based on Figure 5 Generates traffic and control transmission frames and multiframes spread over K channels. The QPSK modulator generates in-phase and quadrature-phase I, Q frames, which are filtered by two TX filters. The I, Q filtered frames are dig...