Title of Invention

"WIRELESS LOCAL LOOP SYSTEM FOR HANDLING INCOMING CALLS"

Abstract The present invention relates to a wireless local loop (WLL) system for handling incoming calls. The present invention solves a major constraint in network when all configured radio/traffic channels of WLL system are busy or faulty. In such conditions, the calling subscriber gets ring back tone instead of busy tone as all the analog subscriber ports remain in no-loop state even when no free radio channel is available. According to present invention, a maintenance port is created in one of the subscriber ports As soon as the radio/traffic channels become busy or faulty the state of maintenance port is changed from on-hook to off-hook state so that subscriber gets a busy tone. When the radio/traffic channels become free, the status of maintenance port changes from off-hook to on-hook state. Local exchange will scan the maintenance port state. If the maintenance port is in on-hook state the calling subscriber will get a ring back tone and called subscriber will be fed with ringer.
Full Text The present invention relates to a wireless local loop system for handling incoming calls.
The embodiment of the invention resides in the development and implementation of system for handling incoming calls to wireless in local loop (WLL) system with two wire subscriber interface.
On two wire subscriber interface, line condition expected or generated are loop (off-hook) or no-loop (on-hook). These conditions leads into major constraint in network when all the configured radio/traffic channels of wireless in local loop system are busy or faulty. Calling subscriber gets ring back tone (RBT) instead of busy tone, because the status of all the analog subscriber ports remains in on-hook state, whereas towards the wireless in local loop subscriber no free radio channel is available.
Due to the vast expansion of telecommunication network, the necessity of wireless in local loop subscriber has arisen because of limitation of laying additional cables in Metropolitan cities and congested Remote areas.
Various possible solutions suggested for the reduction of constraints in existing
implementation are:
-the off-hook condition on the port where incoming call is received or
- whenever all the radio channels are either busy or faulty, the status of all free analog
subscriber ports shall be made off-hook. As soon as even one radio channel becomes
free, the status of all the analog subscriber ports should be made on-hook.
However, on implementation, both the above referenced solutions have been observed to be not the proper solution as in the first instance the off-hooking condition leads to the charging of calling subscriber whereas actual call is not matured and in the second instance toggling of off-hook /on-hook conditions on all free analog subscriber ports leads to the artificial overload condition due to increased processor occupancy and degradation of services.

To overcome these existing problems it has been found that out of N number of analog subscriber ports towards the wireless in local loop system, the Nth port will be designated as maintenance port to indicate the availability /non-availability of radio channels in wireless in local loop systems.
Calling subscriber gets ring back tone (RBT) instead of busy tone, because the status of the analog subscriber ports are still in ON-HOOK state, whereas towards the wireless in local loop subscriber, no free radio channels is available.
The objective of the invention is to provide the solution to overcome the limitation of connecting two wire subscriber interface between local exchange and wireless in local loop system.
The innovativeness of the system is that it requires not only modification in the software of local exchange but also wireless in local loop system to control hardware when all the radio /traffic channels are busy/free. Wireless in loop system will give trigger to hardware such that the defined maintenance port will drive loop/no loop and by sensing the loop/no-loop, local exchange will take the necessary action in the form of giving busy tone or allowing the call to pass on to wireless in local loop subscriber. This will even make it possible to connect wireless in local loop system to local exchanges already working in the field on two wire subscriber interface.
There are three sub-systems operating for the incoming and outgoing calls as: 1) ADMIN SUBSYSTEM:
Local exchange and wireless in local loop system are connected by "N" number of two wire subscriber interface having control over the numbering plan. "N-l" number of actual subscribers data is created and the Nth subscriber port is configured as maintenance port in both Local Exchange and wireless in local loop. A dummy subscriber number is to be associated with this maintenance port at both ends.

Physically no wireless in local loop Subscriber will be connected to this maintenance port. This port is used only to see the status of free available radio channel.
2)MAINTENANCE SUBSYSTEM
Loop /No-loop are the only signals possible over two wire subscriber interface. As soon as all the radio channels become busy or faulty, wireless in local loop system maintenance sub-system will change the state of maintenance port from ON-HOOK to OFF-HOOK. Hence, depending upon the availability of free radio channel maintenance port status will toggle and drive loop on the port, which will be sensed by local exchange as no free radio channel are available. Even if the single radio/ traffic channel becomes free, the status of maintenance port will change from OFF-HOOK to ON-HOOK state and drive no loop on the port, which will be secured by local exchange as free radio channels are available and call can mature .
3)CALL PROCESSING SUBSYSTEM
For any incomig calls for wireless in local loop subscribers, local exchange will first scan the maintenance port state. If the maintenance port is in ON-HOOK state incoming call will be passed to wireless in local loop subscriber. Calling subscriber will get the ring-back tone whereas called subscriber will be fed with ringer, similarly for any incoming call for wireless in local loop subscribers if scanning of maintenance port shows state OFF-HOOK, busy tone will be fed to calling subscriber by local exchange.
Accordingly, the subject invention relates to a wireless local loop system for handling incoming calls comprising;
a local exchange;
a wireless local loop system connected by plurality of pairs of wire subscriber interfaces;characterised used in that is provided
a maintenance port created in one of the free subscriber interface; a dummy subscriber number associated with said maintenance port;

means for changing the on hook position to off-hook position of the said maintenance port wherein as soon as all the radio channels become busy or faulty wireless in local maintenance sub-system will change the state of maintenance port from the on-hook to off-hook state when a single radio/traffic channel becomes free,
the status of maintenance port will change from off-hook to on-hook state and drive
no loop on the port secured by local exchange as free radio channels available to
mature the call.
In the wireless local loop system if the maintenance port is on-hook condition, call be put through and ring back tone will be fed to calling subscriber and ring will be fed to called wireless local loop subscriber and if the said maintenance port is in off-hook condition, a busy tone will be fed to the calling subscriber.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRA WINGS
Figure 1 depicts the connection of wireless in local loop system to Local
Exchange in existing PSTN network using two wire analog subscriber interface.
Figure 2 depicts the off-hook condition on the maintenance port
Figure 3 depicts the off-hook condition on the maintenance port where busy
tone will be fed to the calling subscriber.
DETAILED DESCRIPTION OF THE DRAWINGS
When there is no free available radio channel because all may be either busy or faulty, wireless in local loop system (C) will drive "OFF - HOOK" condition on defined maintenance port towards local exchange(B) and when there is free available radio channel, wireless in local loop system (C) will drive "ON-HOOK" condition on defined maintenance port towards local exchange.

Local exchange (B) will first check the status of defined maintenance port whenever there is an incoming call in the local exchange for wireless in local loop subscriber(C),
As shown in figure 2 if on this maintenance port "ON-HOOK" condition is observed, call will be put through and ring back tone (RBT) will be fed to calling subscriber and ring will be fed to the called wireless in local loop subscriber
And if on this maintenance port "OFF-HOOK" condition is observed, busy tone will be fed to calling subscriber
Hence, the subject invention with improvements in the local exchange and wireless in local loop system, makes it possible to connect wireless in local loop system to local exchange on two wire subscriber interface and thus boosting the availability of telecom services to subscribers in remote/rural areas and congested metros.
The subject application is a mere statement and should not be construed to restrict the scope of the invention.



WE CLAIM:-
1. A wireless local loop system for handling incoming calls comprising;
a local exchange;
a wireless local loop system connected by plurality of pairs of wire subscriber interfaces; characterized in that
a maintenance port is provided in one of the free subscriber interface; a dummy subscriber number is associated with said maintenance port;
means as herein described is provided for changing the on hook position to off-hook position of the said maintenance port wherein as soon as all the radio channels become busy or faulty wireless in local maintenance sub-system will change the state of maintenance port from the on-hook to off-hook state when a single radio/traffic channel becomes free, the status of maintenance port will change from off-hook to on-hook state and drive no loop on the port secured by local exchange as free radio channels available to mature the call.
2. A wireless local loop system as claimed in claim 1, wherein the said
means for changing the on hook position to off-hook position is a call
processing subsystem.
3. A wireless local loop system as claimed in claim 1, wherein in the
event the maintenance port is on-hook condition, call is put through and ring
back tone is fed to calling subscriber and ring is fed to called wireless local
loop subscriber while in case the said maintenance port is in off-hook
condition, a busy tone is fed to the calling subscriber.

4. A wireless local loop system for handling incoming calls substantially as herein before described with reference to the accompanying drawings.

Documents:

1420-del-1998-abstract.pdf

1420-del-1998-claims.pdf

1420-del-1998-correspondence-others.pdf

1420-del-1998-correspondence-po.pdf

1420-del-1998-description (complete).pdf

1420-del-1998-drawings.pdf

1420-del-1998-form-1.pdf

1420-del-1998-form-19.pdf

1420-del-1998-form-2.pdf

1420-del-1998-form-4.pdf

1420-del-1998-form-5.pdf

1420-del-1998-gpa.pdf

1420-del-1998-petition-others.pdf

abstract.jpg


Patent Number 230580
Indian Patent Application Number 1420/DEL/1998
PG Journal Number 11/2009
Publication Date 13-Mar-2009
Grant Date 27-Feb-2009
Date of Filing 27-May-1998
Name of Patentee CENTRE FOR DEVELOPMENT OF TELEMATICS
Applicant Address 9TH FLOOR, AKBAR BHAWAN, CHANAKYAPURI, NEW DELHI-110021, INDIA
Inventors:
# Inventor's Name Inventor's Address
1 YOGESH KUMAR PANDEY CENTRE FOR DEVELOPMENT OF TELEMATICS TELECOM TECHNOLOGY CENTRE OF GOVERNMENT OF INDIA, A GOVERNMENT OF INDIA UNDERTAKING OF 9TH FLOOR, AKBAR BHAWAN, CHANAKYAPURI, NEW DELHI-110021, INDIA
PCT International Classification Number H04L
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA