FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules  2005

COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

TITLE OF THE INVENTION
“A Method and System for Overload Detection and Control in a network”
APPLICANTS:
Name Nationality Address
Alcatel Lucent France 3  avenue Octave Gréard 75007 Paris 
France.

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

TECHNICAL FIELD
[001] The embodiments herein relate to an overload reduction system in a Communication Network and  more particularly  to achieving overload reduction by dropping selected calls in a Communication Network.

BACKGROUND
[002] Any system that can be used for communicating data between two points is called a communication system. Many types of communication systems are in use such as wireless  wired etc. Type of communication networks are chosen based on the area of application. Different communication systems vary in their data transfer capacity  range  number of systems supported etc. One of the major problems faced by communication networks is overloading of the system.
[003] Overloading of a communication system happens when the load requirement exceeds the permitted system capacity. Every communication system is assigned with certain capacity in terms of the number of systems that can be supported  data rate supported etc. There are certain situations where the data rate usage of the systems exceeds the maximum permitted capacity. Such situations results in overloading of systems which in turn affect the stability of the system.
[004] One of the existing systems tries to overcome this situation by rejecting incoming requests for a new session when the processor occupancy of the system exceeds a predefined threshold. But this method is not effective as the existing processes still needs to do some processing to receive  parse and identify the message before discarding it which might be undesirable in an already overloaded system. Also  in this case the control measures are applied at a stage when the system is slow to react. In another method  the system drops data packets upon arrival at the concerned subsystem so as to manage congestion/overload situation. However  this method may affect users irrespective of the resource usage by the users. For example  packets belonging to a user who might not be consuming much of the resource may be dropped  whereas packets of a user who is using a large amount of resource may not be affected  as he/she was accessing the system resources before the other user. Further in this system  the packets would have already used the network resources by the time the control measures are applied. In another method  the system mutes the access terminal during overload condition  while still maintaining the connection with the access terminal. This method has the disadvantage of holding onto network resources for maintaining the connection  even if no data transfer is taking place. In such a case  the access terminal cannot be served by other sub systems which may be less loaded and are capable of providing better service to the access terminal.

SUMMARY
[005] In view of the foregoing  an embodiment herein provides a method for reducing load in a Wireless Network  the method comprising of checking if processor occupancy of the wireless network is greater than a first threshold value; dropping session belonging to at least one user  wherein the session is a best effort connection  if processor occupancy of the wireless network is greater than the first threshold value; and informing the at least one user to attempt to reconnect to the network after a first pre-defined time interval. The session belonging to the at least one user is considered suitable for dropping based on a plurality of parameters  wherein the parameters comprise of Quality of Service (QoS) subscribed by the at least one user; Packets/second for the at least one user; Priority of the at least one user; or an identification means to identify priority of the at least one user. The packets/second is calculated from first packet received from the at least one user over a second pre-defined time interval.
[006] Also  disclosed herein is a network controller in a Wireless Network  the network controller comprising at least one means configured for checking if processor occupancy of the wireless network is greater than a first threshold value; dropping session belonging to at least one user  if processor occupancy of the wireless network is greater than the first threshold value; and informing the at least one user to attempt to reconnect to the network after a first pre-defined time interval. The network controller is further configured for dropping session belonging to the at least one based on a plurality of parameters  wherein the parameters comprise of Quality of Service (QoS) subscribed by the at least one user; Packets/second for the at least one user; Priority of the at least one user; or An identification means to identify priority of the at least one user. The network controller is further configured for calculating the packets/second from first packet received from the at least one user. The network controller is further configured for calculating packets/second for the user over a second pre-defined time interval.
[007] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES
[008] The embodiments herein will be better understood from the following detailed description with reference to the drawings  in which:
[009] FIG. 1 illustrates a general block diagram of a communication network as disclosed in the embodiments herein;
[0010] FIG. 2 illustrates a block diagram which shows various components of a network controller as disclosed in the embodiments herein; and
[0011] FIG. 3 illustrates a flow diagram which describes the process of operation of proposed overload control system as disclosed in the embodiments herein.

DETAILED DESCRIPTION OF EMBODIMENTS
[0012] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly  the examples should not be construed as limiting the scope of the embodiments herein.
[0013] The embodiments herein disclose a system and method for overload reduction in a communication system/network by dropping selected calls in a communication network. Referring now to the drawings  and more particularly to FIGS. 1 through 3  where similar reference characters denote corresponding features consistently throughout the figures  there are shown embodiments.
[0014] FIG. 1 illustrates a general block diagram of a communication network as disclosed in the embodiments herein. The system comprises a network 101 and multiple client systems 105. The network 101 further comprises a transmitter 102  network controller 103 and receiver 104. In an embodiment  the network 101 may comprise cables or wireless or satellite means or any other means for communicating data from one point to another. In another embodiment  the client device may comprise laptop  PDA  mobile phones and/or any other communication device. The client systems 105 try to access the network 101. In an embodiment  the client device 105 may try to establish wired and/or wireless connection with the network 101. The network controller 103 present in the network 101 manages the connection of all the client systems 105 with the network 101. In an embodiment  the network components are capable of checking the network traffic and also the Processor Occupancy (PO) levels of the system. In another embodiment  the network 101 is capable of detecting an overload condition in the network and terminating selected calls based upon certain criteria so as to overcome the network traffic issue. The receiver 104 receives requests from the client systems 105 and passes the received requests to the network controller 103. The network controller 103 processes the requests and gives feedback. The transmitter 102 sends the network responses to the client systems 105.
[0015] FIG. 2 illustrates a block diagram which shows various components of a network controller as disclosed in the embodiments herein. The network controller further comprises a Signaling module 201  Traffic module 202 and a Controller module 203. The traffic module 202 accepts and processes the client requests. In an embodiment  the traffic module is capable of periodically checking the amount of packet data transfer across the network. In another embodiment  the traffic module 202 detects the network overload condition by analyzing the data traffic across the network 101. The controller module 203 checks the Processor Occupancy (P.O) level of the system as soon as the overload condition is detected. Once the network controller 103 detects an increase in the network traffic and processor occupancy (P.O)  it decides to close certain connections based upon certain criteria. The signaling module 201 alerts the user regarding closure of connection and also provides a certain time period before which that particular user is not supposed to request a new connection.
[0016] FIG. 3 illustrates a flow diagram which describes the process of operation of proposed overload control system  as disclosed in the embodiments herein. The proposed system is capable of detecting an overload condition in the network  targeting users who are responsible for the overload condition in the network based upon certain criteria and closing their connections thereby reducing the load on the network.
[0017] The proposed system is initially applied to a Network Controller (NC) with multiple processors sharing the call processing activities. In an embodiment  the network controller can be a Radio Network Controller (RNC). In another embodiment  the proposed system can be applied to any communication network such as wired/ wireless  2G  EVDO  LTE etc. The system determines the connections to be closed at the time of overloading based upon certain parameters. Such parameters include and are not limited to data rate  priority of the user and total connection up time for each user.
[0018] The RNC present in the system periodically measures/calculates (301) the packet rate for each user. In order to do this  for each user  incoming packet rate is calculated on a continuous basis from the point the first packet arrives even before the overloading condition occurs. In an embodiment  Packets per second is calculated using sliding window protocol. System measures the number of packets received from that user in t1 seconds where t1 is a predetermined time period which can be modified based on need of the system. Further  the system calculates average of packet rates calculated in different time intervals t1  t2  t3 and so on to calculate average packet rate. Then the system checks (302) if the calculated data rate is greater than the preset threshold value or not. If the system finds out that no users are exceeding the permitted data rate  then the system performs the check (302) in periodic intervals. If the calculated data rate is found to be greater than the set threshold value  then the system samples (303) the packet rates into ‘n’ windows where n is a preset number. Then the system checks (304) if the packet rate is greater than the threshold value for atleast ‘x’ windows where ‘x’ is predetermined number provided x<n. If in ‘x’ windows or more  the data rate is not greater than the threshold value  then the user is allowed to continue (305) the packet transfer. If the system finds out that the packet rate is greater than the preset threshold for atleast ‘x’ windows  then the system checks (306) if the Processor Occupancy (PO) is greater than the permitted limit or not. If the processor occupancy is not greater than the permitted value  the user is allowed to continue (305) with the data transfer. If the processor occupancy is greater than the permitted value  then the system checks (307) if the user priority is high or not. In an embodiment  the user priority is automatically calculated by the system for each user based upon the application and the Quality of Service (QOS) subscribed by the user. If the user priority is found to be high  then the user is allowed (305) to continue the data transfer. If the user priority is less  then the system decides to terminate (308) that connection. For this purpose  RNC sends ConnectionClose to the selected access terminal. In an embodiment  the connections/sessions so terminated are best effort connections. Along with this  RNC deprioritizes (309) the user and indicate a particular time delay after which the user can again request for access to the resource. In an embodiment  “deprioritizing” of user ensures that the particular user does not request for a resource before a specified/derived delay. These processes are repeated for ‘m1’ users in t2 time. In another embodiment  the system allocates a less loaded resource when the user requests for a new connection after the mentioned time delay.
[0019] The various actions in method 300 may be performed in the order presented  in a different order or simultaneously. Further  in some embodiments  some actions listed in FIG. 3 may be omitted.
[0020] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The network elements shown in Figs. 1 and 2 include blocks which can be at least one of a hardware device  or a combination of hardware device and software module.
[0021] The embodiment disclosed herein specifies a system for overload reduction in a communication system/network. The mechanism allows overloading reduction in a communication network providing a system thereof. Therefore  it is understood that the scope of the protection is extended to such a program and in addition to a computer readable means having a message therein  such computer readable storage means contain program code means for implementation of one or more steps of the method  when the program runs on a server or mobile device or any suitable programmable device. The method is implemented in a preferred embodiment through or together with a software program written in e.g. Very high speed integrated circuit Hardware Description Language (VHDL) another programming language  or implemented by one or more VHDL or several software modules being executed on at least one hardware device. The hardware device can be any kind of device which can be programmed including e.g. any kind of computer like a server or a personal computer  or the like  or any combination thereof  e.g. one processor and two FPGAs. The device may also include means which could be e.g. hardware means like e.g. an ASIC  or a combination of hardware and software means  e.g. an ASIC and an FPGA  or at least one microprocessor and at least one memory with software modules located therein. Thus  the means are at least one hardware means and/or at least one software means. The method embodiments described herein could be implemented in pure hardware or partly in hardware and partly in software. The device may also include only software means. Alternatively  the invention may be implemented on different hardware devices  e.g. using a plurality of CPUs.
[0022] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can  by applying current knowledge  readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept  and  therefore  such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore  while the embodiments herein have been described in terms of preferred embodiments  those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the claims as described herein.

We Claim:-
1. A method for reducing load in a Wireless Network  said method comprising of
Checking if processor occupancy of said wireless network is greater than a first threshold value;
Dropping session belonging to at least one user  if processor occupancy of said wireless network is greater than said first threshold value; and
Informing said at least one user to attempt to reconnect to said network after a first pre-defined time interval.
2. The method  as claimed in claim 1  wherein said session is a best effort connection.
3. The method  as claimed in claim 1  wherein session belonging to said at least one user is considered suitable for dropping based on a plurality of parameters  wherein said parameters comprise of
Quality of Service (QoS) subscribed by said at least one user;
Packets/second for said at least one user;
Priority of said at least one user; or
An identification means to identify priority of said at least one user.
4. The method  as claimed in claim 3  wherein said packets/second is calculated from first packet received from said at least one user.
5. The method  as claimed in claim 3  wherein said method further comprises of calculating packets/second for said user over a second pre-defined time interval.
6. A network controller in a Wireless Network  said network controller comprising at least one means configured for
Checking if processor occupancy of said wireless network is greater than a first threshold value;
Dropping session belonging to at least one user  if processor occupancy of said wireless network is greater than said first threshold value; and
Informing said at least one user to attempt to reconnect to said network after a first pre-defined time interval.

7. The network controller  as claimed in claim 6  wherein said network controller is further configured for dropping session belonging to said at least one based on a plurality of parameters  wherein said parameters comprise of
Quality of Service (QoS) subscribed by said at least one user;
Packets/second for said at least one user;
Priority of said at least one user; or
An identification means to identify priority of said at least one user.

8. The network controller  as claimed in claim 7  wherein said network controller is further configured for calculating said packets/second from first packet received from said at least one user.

9. The network controller  as claimed in claim 7  wherein said network controller is further configured for calculating packets/second for said user over a second pre-defined time interval.

06th SEP  2011

Dr. Kalyan Chakravarthy
Patent Agent
ABSTRACT
The embodiments disclosed herein relates to a system and method for overcoming the overload situation in a communication network. The system overcomes overloading condition by closing selected connections. The proposed system periodically evaluates if a network overload condition exists. If an overload condition is recognized in the network  based upon certain criteria  the system targets certain users and recovers the resources allocated to them. The system also deprioritizes the user. Further  the system sends a notification message to the user regarding the termination of the connection and also provides a delay time  or a parameter from the delay time can be derived  before which the user is not supposed to make a new connection request. Further  if the user sends a new connection request after the mentioned/derived delay time  a less loaded resource may be allocated to the user.FIG. 3