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Rolling Inhibit Overload Protection Disclosure Number: IPCOM000216052D
Publication Date: 2012-Mar-21

Publishing Venue

The Prior Art Database

Related People

Miller, Karl: INVENTOR [+1]


A Concept of Rilling Inhibit is applied. Each MME rotates their assignments of ?inhibited? eNBs with an Update Interval (U) and restarts/ repeats the sequence periodically (period T), so no one eNB stays in a geographical outage permanently Each eNB is ensured at least U seconds of potential access every T seconds Load Reduction ratios of (T-U)/U are possible, while outage for any one eNB is limited to a max of (T-U) seconds every T seconds. For the Motorola LTE WBC(MME) product, this is being implemented with T=6 seconds and U= 30 seconds

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By Karl Miller and Greg Freeland

Motorola, Inc.

Motorola Solutions Networks



An apparatus and method for rolling inhibit overload protection in a communication network is described.  This involves a step of detecting a level of communication traffic congestion in a Network Element pool followed by a step which includes sending Overload/Stop instructions from all Network Elements in the pool to at least one base station to inhibit the at least one base station.  A following step includes inhibiting communication at the at least one base station.  This is followed by rotating the sending and inhibiting steps among all base stations and by adjusting the size of the base station set to be inhibited in order to achieve a wide level of load reduction for the Network Element pool at predetermined inhibit time periods.

The result of this method is efficient load reduction throughout the Network Element pool while avoiding geographical outages in the network.



Overload in various forms of communication networks often utilize feedback flow control mechanisms to force source elements in the network to reduce or stop the forwarding of traffic under overload conditions.  These mechanisms work well for low levels of overloading.  However with high levels of overloading, these mechanisms can incur negative consequences in the network.  For example, in large networks with aggregation points where many sending network nodes are feeding a small number of receiver nodes, the use of such feedback flow control mechanisms in response to heavy overloading can result in geographical outages.  That is, a large number of the sending nodes can be essentially disconnected from the network for the duration of the overload condition, providing what is essentially a network outage for the affected sending nodes.

The problem then is how to achieve significant load reduction in the pursuit of overload control in a large network without incurring geographical outages for sending nodes within the network.



The solution described in this publication is a method for applying feedback flow control in such a manner as to achieve high levels of load reduction, even while under extreme overloading, without incurring geographical outages for sending nodes within the network.



In 4G wireless telecommunication networks, such as Worldwide Interoperability for Microwave Access (WiMAX) communication network or Long Term Evolution (LTE) communication network, a Mobility Management Entity (MME) is the key control node for the access-network.  The MME manages one or more evolved eNodeBs (eNB) in a region.  Each eNB serves one or more user equipment (UE) in its geographic area.  The MME is responsible for UE tracking and paging procedures, authentication and authorization of the UE, and it is involved in the bearer activation/deactivation process.  It is also responsible for...