FIELD OF THE INVENTION

The invention is related to the field of communication systems and, in particular, to sharing of radio resources between Machine Type Communications (MTC) and non-MTC.

BACKGROUND

Machine Type Communications (MTC) or Machine-to-Machine (M2M) communications refer to technologies that allow devices to communicate with no or little human intervention. MTC devices store data, and transmit the data to other MTC devices or an MTC server over a network, such as a cellular network. For example, an MTC device may be attached to a gas or electric meter, and the MTC device periodically (e.g., weekly, monthly, etc.) transmits a meter reading to an MTC server, such as at the utility company.

The amount of data exchanged between MTC devices is typically very small, such as less than a few bytes. Because MTC devices send or receive only small amounts of data, the exchanges of data are considered “small data transmissions”. The amount that is considered “small” may depend on individual network operators.

MTC continues to increase over core networks. Thus, efficient use of network resources for MTC, especially radio resources, is important to network operators.

SUMMARY

Embodiments described herein provide enhanced sharing of radio resources on the air interface between MTC transmissions and non-MTC transmissions. A resource sharing window is defined for scheduling radio resources between MTC and non-MTC. A resource sharing window includes an MTC-On interval where MTC transmissions are allowed, and an MTC-Off interval where MTC transmissions are prohibited. Toward the end of an MTC-Off interval, the Modulation and Coding Scheme (MCS) for a non-MTC device may be lowered to increase the likelihood that a transmission involving the non-MTC device is successfully received and decoded by the destination (i.e., the device for a downlink transmission and a base station for an uplink transmission). The MCS is typically selected for a device based on channel quality identified for the device, and an adjusted MCS as described herein is lower than the MCS which would be selected based on channel quality. One technical benefit of using an adjusted MCS toward the end of an MTC-Off interval is that a Hybrid Automatic Repeat Request (HARQ) process for the transmission will more likely complete before the end of the MTC-Off interval, instead of being suspended during the next MTC-On interval, to more efficiently utilize network resources.

One embodiment comprises an access network element of an access network. The access network element includes a radio interface component configured to communicate with a plurality of devices over an air interface, and a pattern database configured to store a sharing pattern that maps radio resources on a physical layer of the air interface between MTC radio resources and non-MTC radio resources. The access network element further includes a scheduling mechanism configured to identify a resource sharing window having an MTC-On interval where MTC is allowed, and having an MTC-Off interval where MTC is prohibited. Between a threshold time and an end of the MTC-Off interval, the scheduling mechanism is configured to select an adjusted MCS for a legacy device of the plurality of devices that is lower than a standard MCS for the legacy device selected based on channel quality information for the legacy device, to allocate a set of the MTC radio resources to the legacy device based on the sharing pattern, and to schedule a non-MTC transmission for the legacy device on the set of the MTC radio resources based on the adjusted MCS.

In another embodiment, the scheduling mechanism is configured to select among multiple adjusted MCSs for the legacy device that are lower than the standard MCS, where the adjusted MCSs decrease from the threshold time to the end of the MTC-Off interval.

In another embodiment, a time period from the threshold time to the end of the MTC-Off interval comprises an adjustment period, the adjustment period comprises a plurality of sub-periods in sequence that each specify a signal-to-interference-plus-noise ratio (SINR) reduction value, and SINR reduction values increase from a first one of the sub-periods in the sequence to a last one of the sub-periods in the sequence.

In another embodiment, the scheduling mechanism is configured to identify the SINR reduction value for a sub-period of the plurality of sub-periods, to determine an estimated SINR for the legacy device based on the channel quality information, to subtract the SINR reduction value for the sub-period from the estimated SINR to determine an adjusted SINR for the legacy device, and to select the adjusted MCS for the legacy device based on the adjusted SINR.

In another embodiment, the scheduling mechanism is configured to determine whether the SINR reduction value for the sub-period equals a threshold value, and to determine that the MTC radio resources are not available to the legacy device when the SINR reduction value equals the threshold value.

In another embodiment, the scheduling mechanism is configured to schedule the non-MTC transmission for the legacy device on the set of the MTC radio resources of an uplink channel.

In another embodiment, the scheduling mechanism is configured to schedule the non-MTC transmission for the legacy device on the set of the MTC radio resources of a downlink channel.

In another embodiment, before selecting the adjusted MCS for the legacy device, the scheduling mechanism is configured to mark the MTC radio resources as unavailable, to allocate a set of the non-MTC radio resources to the legacy device, to select the standard MCS for the legacy device, and to determine a transport block size for the legacy device based on the standard MCS. After selecting the adjusted MCS for the legacy device, the scheduling mechanism is configured to determine an adjusted transport block size for the legacy device according to the adjusted MCS, and to determine whether the adjusted transport block size is increased over the transport block size determined according to the standard MCS. When the adjusted transport block size is not increased, the scheduling mechanism is configured to allocate the set of the MTC radio resources to the legacy device that were previously marked as unavailable until the adjusted transport block size is increased.

In another embodiment, the scheduling mechanism is configured to request a legacy load and an MTC load in the access network, to determine whether the legacy load exceeds a first high threshold, and to set a duration of the MTC-On interval for a next resource sharing window to a minimum when the legacy load exceeds the first high threshold. When the legacy load does not exceed the first high threshold, the scheduling mechanism is configured to determine whether the legacy load is less than a first low threshold, and to set the duration of the MTC-On interval for the next resource sharing window to a maximum when the legacy load is less than the first low threshold. When the legacy load is not less than the first low threshold, the scheduling mechanism is configured to determine whether the MTC load exceeds a second high threshold, and to increase the duration of the MTC-On interval for the next resource sharing window when the MTC load exceeds the second high threshold. When the MTC load does not exceed the second high threshold, the scheduling mechanism is configured to determine whether the MTC load is less than a second low threshold, and to decrease the duration of the MTC-On interval for the next resource sharing window when the MTC load is less than the second low threshold. When the MTC load is not less than the second low threshold, the scheduling mechanism is configured to maintain the duration of the MTC-On interval in the next resource sharing window.

Another embodiment comprises a method of sharing an air interface between an access network element of an access network and a plurality of devices. The method comprises storing a sharing pattern that maps radio resources on a physical layer of the air interface between MTC radio resources and non-MTC radio resources, and identifying a resource sharing window having an MTC-On interval where MTC is allowed, and having an MTC-Off interval where MTC is prohibited. Between a threshold time and an end of the MTC-Off interval, the method comprises selecting an adjusted MCS for a legacy device of the plurality of devices that is lower than a standard MCS for the legacy device selected based on channel quality information for the legacy device, allocating a set of the MTC radio resources to the legacy device based on the sharing pattern, and scheduling a non-MTC transmission for the legacy device on the set of the MTC radio resources based on the adjusted MCS.

In another embodiment, selecting the adjusted MCS for the legacy device comprises selecting among multiple adjusted MCSs for the legacy device that are lower than the standard MCS. The adjusted MCSs decrease from the threshold time to the end of the MTC-Off interval.

In another embodiment, a time period from the threshold time to the end of the MTC-Off interval comprises an adjustment period, the adjustment period comprises a plurality of sub-periods in sequence that each specify a SINR reduction value, and SINR reduction values increase from a first one of the sub-periods in the sequence to a last one of the sub-periods in the sequence.

In another embodiment, selecting the adjusted MCS comprises identifying the SINR reduction value for a sub-period of the plurality of sub-periods, determining an estimated SINR for the legacy device based on the channel quality information, subtracting the SINR reduction value for the sub-period from the estimated SINR to determine an adjusted SINR for the legacy device, and selecting the adjusted MCS for the legacy device based on the adjusted SINR.

In another embodiment, the method further comprises determining whether the SINR reduction value for the sub-period equals a threshold value, and determining that the MTC radio resources are not available to the legacy device when the SINR reduction value equals the threshold value.

In another embodiment, scheduling the non-MTC transmission for the legacy device comprises scheduling the non-MTC transmission for the legacy device on the set of the MTC radio resources of an uplink channel.

In another embodiment, scheduling the non-MTC transmission for the legacy device comprises scheduling the non-MTC transmission for the legacy device on the set of the MTC radio resources of a downlink channel.

In another embodiment, before selecting the adjusted MCS for the legacy device, the method comprises marking the MTC radio resources as unavailable, allocating a set of the non-MTC radio resources to the legacy device, selecting the standard MCS for the legacy device, and determining a transport block size for the legacy device based on the standard MCS. After selecting the adjusted MCS for the legacy device, the method comprises determining an adjusted transport block size for the legacy device according to the adjusted MCS, determining whether the adjusted transport block size is increased over the transport block size determined according to the standard MCS, and when the adjusted transport block size is not increased, allocating the set of the MTC radio resources to the legacy device that were previously marked as unavailable until the adjusted transport block size is increased.

In another embodiment, the method further comprises requesting a legacy load and an MTC load in the access network, determining whether the legacy load exceeds a first high threshold, and setting a duration of the MTC-On interval for a next resource sharing window to a minimum when the legacy load exceeds the first high threshold. When the legacy load does not exceed the first high threshold, the method further comprises determining whether the legacy load is less than a first low threshold, and setting the duration of the MTC-On interval for the next resource sharing window to a maximum when the legacy load is less than the first low threshold. When the legacy load is not less than the first low threshold, the method further comprises determining whether the MTC load exceeds a second high threshold, and increasing the duration of the MTC-On interval for the next resource sharing window when the MTC load exceeds the second high threshold. When the MTC load does not exceed the second high threshold, the method further comprises determining whether the MTC load is less than a second low threshold, and decreasing the duration of the MTC-On interval for the next resource sharing window when the MTC load is less than the second low threshold. When the MTC load is not less than the second low threshold, the method further comprises maintaining the duration of the MTC-On interval in the next resource sharing window.

Another embodiment comprises a non-transitory computer readable medium embodying programmed instructions executed by a processor, wherein the instructions direct the processor to implement an access network element of an access network configured to communicate with a plurality of devices over an air interface. The access network element is configured to store a sharing pattern that maps radio resources on a physical layer of the air interface between MTC radio resources and non-MTC radio resources. The access network element is configured to identify a resource sharing window having an MTC-On interval where MTC is allowed, and having an MTC-Off interval where MTC is prohibited. Between a threshold time and an end of the MTC-Off interval, the access network element is configured to select an adjusted MCS for a legacy device of the plurality of devices that is lower than a standard MCS for the legacy device selected based on channel quality information for the legacy device, to allocate a set of the MTC radio resources to the legacy device based on the sharing pattern, and to schedule a non-MTC transmission for the legacy device on the set of the MTC radio resources based on the adjusted MCS.

Another embodiment comprises an access network element of an access network. The access network element includes a means for communicating with a plurality of devices over an air interface, and a means for storing a sharing pattern that maps radio resources on a physical layer of the air interface between MTC radio resources and non-MTC radio resources. The access network element includes a means for identifying a resource sharing window having an MTC-On interval where MTC is allowed, and having an MTC-Off interval where MTC is prohibited. Between a threshold time and an end of the MTC-Off interval, the access network element includes a means for selecting an adjusted MCS for a legacy device of the plurality of devices that is lower than a standard MCS for the legacy device selected based on channel quality information for the legacy device, allocating a set of the MTC radio resources to the legacy device based on the sharing pattern, and scheduling a non-MTC transmission for the legacy device on the set of the MTC radio resources based on the adjusted MCS.

The above summary provides a basic understanding of some aspects of the specification. This summary is not an extensive overview of the specification. It is intended to neither identify key or critical elements of the specification nor delineate any scope of the particular embodiments of the specification, or any scope of the claims. Its sole purpose is to present some concepts of the specification in a simplified form as a prelude to the more detailed description that is presented later.

