Mobile communication system, base station demodulator for said mobile communication system, and method for treminating plurality of ATM lines in base station demodulator

• US 20020001297A1
• Filed: 05/22/2001
• Published: 01/03/2002
• Est. Priority Date: 05/22/2000
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Yamagiwa, Hirofumi
• Granted Patent: US 7,095,721 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 2001/0096 Channel splitting in point-to-point links
• CPC Class Codes: H04L 2012/5607 Radio
• CPC Class Codes: H04L 2012/5647 Cell loss
• CPC Class Codes: H04L 2012/5673 Coding or scrambling
• CPC Class Codes: H04L 2012/5674 Synchronisation, timing recovery or alignment
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

In a method for terminating a plurality of ATM lines for a base station modulator/demodulator in a mobile communication system for data communication between upper stations and a base station by a transmission method wherein ATM cells are mapped utilizing an existing leased line as a physical medium sublayer, when an increase in capacity of the base station necessitates leased line interfaces corresponding to a plurality of upper stations, processing is carried out in such a manner that leased line numbers are added to respective HEC regions of ATM cells sent from each upper station into a leased line interface section, whereby the addition of the function of the leased line interface section involved in an increase in the leased line can be minimized and the additional function can be simply designed utilizing a conventional technique. By virtue of this constitution, a method for receiving a plurality of ATM lines can be realized which can efficiently utilize VCI filters and can distinguish each upper station in a leased line interface section.

Claims

1. A mobile communication system for data communication between upper stations and a base station by a transmission method wherein ATM cells are mapped using a physical medium sublayer, said mobile communication system comprising a plurality of upper stations, a base station, and a physical medium sublayer comprising a plurality of leased line interfaces for connecting the respective upper stations to the base station, wherein

the base station has a demodulator comprising:

means for adding a leased line number to an ATM cell in its HEC region input into a leased line interface section from each upper station; and

means for detecting and processing the added leased line number.

2. The mobile communication system according to claim 1, wherein the physical medium sublayer comprising a plurality of leased line interfaces is an existing leased line, and transmission is carried out in such a state that ATM cells are mapped in a leased line frame format.

3. The mobile communication system according to claim 1, wherein the physical medium sublayer comprising a plurality of leased line interfaces is of a synchronous digital hierarchy (SDH) system, and transmission is carried out in such a state that ATM cells are mapped in a leased line frame format.

4. A base station demodulator in a mobile communication system for data communication between upper stations and a base station by a transmission method wherein ATM cells are mapped using a physical medium sublayer, said base station demodulator comprising:

means for adding a leased line number to the ATM cell in its HEC region sent to a leased line interface section in the base station demodulator from each upper station; and

means for detecting and processing the added leased line number.

5. The base station demodulator according to claim 4, wherein the leased line interface section comprises:

a plurality of sets of a leased line frame trailer, an ATM cell synchronization detector, an ATM HEC error detector, and an HEC corrector, the sets corresponding respectively to a plurality of leased lines; and

one protocol error detector, wherein;

in the leased line frame trailers, synchronization of the frame format of data received from the leased line is carried out;

in the ATM cell synchronization detector, cell synchronization for establishing the boundary position of the cell is carried out for identifying an ATM cell mapped within the frame after the establishment of frame synchronization;

in the ATM HEC error detector, HEC error detection is carried out in the ATM cell which has become detectable by the cell synchronization;

in the HEC corrector, the content of HEC within the ATM header is rewritten to the number of the leased line;

the protocol error detector has a plurality of filters comprising a leased line number detector and a VPI/VCI detector;

the leased line number detector confirms the leased line number of HEC of the input ATM cell and, when the leased line number has been found to be matched, sends the ATM cell to the VPI/VCI detector; and

the VPI/VCI detector confirms VPI/VCI of the ATM header and, when the VPI/VCI has been found to be matched, sends the ATM cell to CPU.

6. A method for terminating a plurality of ATM lines of a base station demodulator in a mobile communication system for data communication between upper stations and a base station by a transmission method wherein ATM cells are mapped using a physical medium sublayer, wherein:

data received from a plurality of leased lines are subjected to the synchronization of the frame format in respective leased line frame trailers;

in an ATM cell synchronization detector, cell synchronization for establishing the boundary position of the cell is carried out for identifying an ATM cell mapped within the frame;

in an ATM HEC error detector, HEC error detection is carried out in the ATM cell which has become detectable by the cell synchronization;

in an HEC corrector, the content of HEC within the ATM header is rewritten to the number of the leased line, and ATM cells are sent from the respective HEC correctors to one protocol error detector;

leased line number detectors respectively in a plurality of filters in the protocol error detector confirm the leased line number of HEC of the input ATM cell and, when the leased line number has been found to be matched, send the ATM cell to a VPI/VCI detector; and

the VPI/VCI detector confirms VPI/VCI of the ATM header and, when VPI/VCI has been found to be matched, sends the ATM cell to CPU.