Inter-rat systems access network (AN) load balance and congestion control mechanism

A method for providing inter-Radio Access Technology (RAT) load-balancing and congestion control when a wireless device attempts to re-select a primary RAT while receiving wireless communication over a secondary RAT that is different from the primary RAT, the method comprising performing the following steps using a network entity in a Radio Access Network (RAN) supporting the secondary RAT:

• broadcasting a message to all idle wireless devices receiving wireless communication over the secondary RAT, wherein the message contains a control function that enables each idle wireless device to activate an inter-RAT load-balancing functionality that controls reselection of the primary RAT;
• providing a group identifier in the broadcast message to identify one or more pre-provisioned groups of idle wireless devices;
• providing one or more group-specific probability threshold values in the broadcast message;
• through the combination of the control function and the group identifier, remotely configuring each idle wireless device from only the identified groups of idle wireless devices to activate the inter-RAT load-balancing functionality, thereby enabling only the identified groups of idle wireless devices to re-select the primary RAT;
• and
• from among the enabled idle wireless devices, allowing only those idle wireless devices to re-select the primary RAT that generate, in response to the activation of the inter-RAT load balance functionality, an individual device-specific random value that is equal to or greater than a respective group-specific probability threshold value associated with an identified group to which the enabled idle wireless device belongs.

A wireless device that is capable of wireless communication over a primary Radio Access Technology (RAT) and a secondary RAT that is different from the primary RAT, wherein the wireless device is in an idle state when receiving wireless communication over the secondary RAT, and wherein the wireless device comprises:

• a transceiver configured to receive a broadcast message from a network entity in a Radio Access Network (RAN) supporting the secondary RAT, wherein the broadcast message contains the following:
• a control function,
• a probability threshold value, and
• a retention timer;
• and
• a processor coupled to the transceiver and configured to perform the following:
• process the control function to activate an inter-RAT load-balancing functionality that controls re-selection of the primary RAT by the wireless device,
• generate a random value in response to the activation of the inter-RAT load balancing functionality,
• compare the generated random value with the received probability threshold value,
• perform re-selection of the primary RAT when the generated random value is equal to or greater than the received probability threshold value, and
• when the generated random value is less than the received probability threshold value, prevent re-activation of the inter-RAT load-balancing functionality until the retention timer expires.

A mobile communication node configured to provide a radio interface to a wireless device that is capable of wireless communication over a primary Radio Access Technology (RAT) and a secondary RAT, wherein the secondary RAT is different from the primary RAT and wherein the mobile communication node is part of a Radio Access Network (RAN) supporting the secondary RAT, the mobile communication node comprising:

• a processor configured to generate a broadcast message containing one of the following:
• a congestion indicator that indicates that the primary RAT is congested, and wherein the congestion indicator, when processed by the wireless device, causes the wireless device to disable re-selection of the primary RAT when the wireless device is in an idle state, and
• a set of non-congestion parameters that includes the following:
• a control function that, when processed by the wireless device, enables the wireless device to activate an inter-RAT load-balancing functionality that controls re-selection of the primary RAT when the wireless device is in the idle state, and
• a probability threshold value,
• wherein, upon activation, the inter-RAT load-balancing functionality causes the wireless device to generate a random value, compare the generated random value with the probability threshold value, and send a first request to the mobile communication node to allow the wireless device to re-select the primary RAT when the generated random value is less than the probability threshold value;
• and
• a transceiver coupled to the processor and configured to perform the following:
• transmit the broadcast message to the wireless device,
• receive the first request from the wireless device to allow the wireless device to re-select the primary RAT, and
• send the received first request to the processor, wherein the processor is configured to process the first request from the wireless device and allow the wireless device to re-select the primary RAT.