SATELLITE (GPS) ASSISTED CLOCK APPARATUS, CIRCUITS, SYSTEMS AND PROCESSES FOR CELLULAR TERMINALS ON ASYNCHRONOUS NETWORKS

• US 20090054075A1
• Filed: 08/23/2007
• Published: 02/26/2009
• Est. Priority Date: 08/23/2007
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Guvelioglu, Ilyas Berk, Boejer, Joergen, Vallauri, Alain
• Granted Patent: US 8,249,616 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/12 wherein the cooperating elements are telecommunication base stations
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message

Abstract

A wireless circuit (1100, 1190) for tracking an incoming signal and for use in a network (2000) having handover from one part (Cell A) of the network to another part (Cell B). The wireless circuit includes a processor (CE 1100) responsive to the incoming signal, the processor (CE 1100) operable to generate pulse edges representing network-based receiver synchronization instances (RSIs), and a timekeeping circuitry (2420, 2430, 2450) including an oscillator circuitry (2162), the timekeeping circuitry (2420, 2430) operable to maintain a set of counter circuitries (2422-2428) including a counter circuitry (2422) operable to maintain at least one network time component based on the RSIs and another counter circuitry (2428) operable at least during handover and during loss of network coverage for maintaining at least one internal time component (NC) based on the oscillator circuitry (2162), the set of counter circuitries (2422-2428) operable to account for elapsing time substantially gaplessly and substantially without overlap between the time components during a composite of network coverage, loss of network coverage and handover, and the timekeeping circuitry further including a time generator (2450) for combining the time components from the set of counter circuitries (2422-2428) to generate an approximate absolute time (SGTB). Other electronic circuits, positioning systems, methods of operation, and processes of manufacture are also disclosed and claimed.

Claims

1. A wireless circuit for tracking an incoming signal and for use in a network having handover from one part of the network to another part, and comprising:

a processor responsive to the incoming signal, said processor operable to generate pulse edges representing network-based receiver synchronization instances (RSIs); and

a timekeeping circuitry including an oscillator circuitry, said timekeeping circuitry operable to maintain a set of counter circuitries including a counter circuitry operable to maintain at least one network time component based on the RSIs and another counter circuitry operable at least during handover and during loss of network coverage for maintaining at least one internal time component based on the oscillator circuitry, the set of counter circuitries operable to account for elapsing time substantially gaplessly and substantially without overlap between the time components during a composite of network coverage, loss of network coverage and handover, and said timekeeping circuitry further including a time generator for combining the time components from the set of counter circuitries to generate an approximate absolute time.

2. An electronic circuit for mobile timekeeping during handover between base stations for cells in a macrocell asynchronous mobile system, the electronic circuit comprising:

a satellite positioning engine;

a cellular engine including a first circuit operable to maintain time by receiver synchronization instances (RSIs) prior to handover and by an internal clock, and including a second circuit providing a strobed time instance between the satellite positioning engine and the cellular engine, and the cellular engine upon handover is operable to continue to maintain time given a change of reception time of unsynchronized RSIs due to handover and a change of propagation delay to the cellular engine due to handover.

3. An electronic circuit for tracking an incoming signal from a network, and comprising:

a processor responsive to the incoming signal, said processor operable to generate pulse edges representing network-based receiver synchronization instances (RSIs);

oscillator circuitry; and

an adjustment circuit operable to adjust the oscillator circuitry in frequency in response to the network-based RSIs from said processor, said adjustment circuit including a time counter circuitry fed from said oscillator circuitry and including a counter operable to maintain a running count between successive RSIs.

4. An electronic circuit for an incoming signal having modulation, and comprising:

a processor responsive to said modulation, said processor operable to supply a received signal S_R and said processor further operable to provide a channel impulse response h and an error-reducing decode output;

a remodulator fed with the channel impulse response from said processor and with the error-reducing decode output, said remodulator operable to generate a remodulated signal S_RM as output;

arithmetic circuitry operable to supply an output related to a phase difference δ

φ

between the received signal S_R and the remodulated signal S_RM;

a frequency lock loop responsive to said phase difference output; and

time counter circuitry responsive to said phase difference output for time correction.

5. A wireless positioning system for use with a cellular network signal, comprising:

a cellular engine having an on-clock and a sleep clock;

a positioning engine coupled to said cellular engine by a strobe line, at least one of said positioning engine and said cellular engine operable to send a first strobe signal having a first strobe edge over said strobe line to the other engine, and said positioning engine further operable to send a message indicating what the positioning time was at the strobe edge, and then suspend operation in said positioning engine;

said cellular engine operable in a first mode to maintain the time based on the positioning time and based on said on-clock at least occasionally synchronized to the cellular network signal, and further operable to enter a sleep mode and maintain the time based on said sleep clock and then reenter the first mode, and said positioning engine operable to send a second strobe signal having a strobe edge over said strobe line to said cellular engine, said cellular engine operable to send a message indicating the maintained time at the second strobe edge based on said on-clock and said sleep clock,

said positioning engine further operable to resume operation and establish an expedited first fix based on the maintained time from said cellular engine.

6. A method of providing estimated time in a system having a satellite receiving engine GE operable for satellite reception and a cellular engine CE operable for cellular reception, the method comprising

sending a first strobe between GE and CE;

generating a satellite time value by GE, corresponding to the first strobe;

generating a cellular time value by CE, corresponding to the first strobe;

monitoring a cellular engine time interval after the first strobe in a manner corrected by the cellular reception;

losing satellite reception in GE followed by regaining satellite reception in GE;

sending a next strobe between GE and CE;

correcting the internal time for use by GE, as a function of the satellite time value corresponding to the first strobe and a time interval between the first strobe and the next strobe;

operating GE to obtain a current satellite time value from satellite reception by GE facilitated by the internal time thus corrected for use by GE;

generating a satellite time value by GE, corresponding to the next strobe; and

successively repeating the method between the generating steps inclusive so that the next strobe is treated as the first strobe for the succeeding repetition therebetween, whereby each repetition includes a single strobe.

7. A method of providing estimated time in a system having a satellite receiving engine GE operable for satellite reception and a cellular engine CE operable for reception from a cellular network, the method comprising

sending a first strobe from GE to CE;

generating a satellite time value by GE corresponding to the first strobe;

generating a cellular time value by CE corresponding to the first strobe;

monitoring a cellular engine time interval after the first strobe in a manner corrected by the reception from the cellular network;

losing satellite reception in GE followed by regaining satellite reception in GE;

sending a next strobe between GE and CE; and

correcting the internal time for use by GE as a function of the satellite time value corresponding to the first strobe and a time interval between the first strobe and the next strobe.

8. An electronic circuit for use with time of arrival signals from a network, the electronic circuit comprising:

a position determination unit operable to generate a global time value and to convey a first global time from said position determination unit as an output;

a first clock greater than 1 MHz, said first clock operable to be powered on and off;

a second clock less than 1 MHz having cycles; and

processing circuitry coupled to said first clock and to said second clock and to said position determination unit, said processing circuitry operable to;

measure a time interval between the time of arrival signals relative to first clock counts and measure a time interval between cycles of said second clock relative to first clock counts;

generate a number n₂ of clock counts of said first clock when said first clock is powered on and generate a number of clock counts n₃ of said second clock while said first clock is powered off; and

project a relatively-accurate subsequent global time based on said first global time and using said measure and generate operations; and

then return said relatively-accurate subsequent global time to said position determination unit to facilitate a subsequent position determination by said position determination unit.

9. A process of manufacturing a telecommunication product comprising

stuffing a printed wiring board (PWB) of the telecommunication product to have cellular engine CE and a satellite positioning engine GE, and an interface including a timestamp line connecting CE and GE, and a telecommunications modem coupled to the CE;

loading software into a non-volatile memory coupled to the CE;

loading operational parameters to the non-volatile memory for configuring the CE with operational parameters for timekeeping, and for operating a frequency lock loop, and parameters representing characteristics of a cellular network;

coupling a user interface to the CE;

operating the CE in response to the non-volatile memory to configure and execute CE operations and communicate with the GE over the timestamp line; and

testing the stuffed PWB for reduced length of time to position fix TTFF due to the communication of the CE with the GE.