Field of Invention
The present application relates to the use of unlicensed spectrum by cellular communication systems, and more specifically, method and apparatus for programmatically virtualizing the unlicensed spectrum so that in a given location within the cellular system, it is utilized only for certain types of flows.
Discussion of Related Art
This invention is concerned with the specification of a method and apparatus for the effective use of the unlicensed spectrum by cellular systems that also have access to licensed spectrum for their operations. The invention programmatically virtualizes the unlicensed spectrum so that in different locations within the cellular network, it is dynamically allocated for different types of packet flows.
A number of related prior art exists. The patent application US 2015/0126207 A1 considers LTE access points (APs) utilizing the unlicensed spectrum by providing measurements to an LTE base station, which in return reallocates the channels in the unlicensed spectrum to individual LTE APs. The disclosure specifies priorities of each frequency band at each LTE AP location based on the level of interference or traffic activity happening in each frequency band.
The patent specification U.S. Pat. No. 9,031,017 B2 considers an LTE base station to transmit for a time period over an unlicensed band after detecting the medium is clear. As part of using the unlicensed spectrum, power control is also carried out to limit the range of interference.
The patent application US 2015/0063098 A1 discloses methods for switching small cells using unlicensed spectrum to low utilization modes to limit the usage of unlicensed spectrum both in time and frequency when the load of small cells drops below a preset threshold.
The patent application WO 2015/009433 A1 specifies a reservation method over the unlicensed spectrum where a base station, after performing a clear channel assessment, broadcasts a first signal during the first time period to announce downlink transmissions to a particular UE over a second time period.
The patent specification U.S. Pat. No. 8,874,124 B2 specifies a dual-band base station that uses one radio access technology in the licensed band (e.g., LTE) and replaces the physical layer communication of the said radio access technology with another physical layer technology to be used over the unlicensed band (e.g., WiFi). The base station in either case is seen as a regular base station to the core network, while from UE perspective it can be seen as a base station or a hot spot access point. UE and the base station compare the conditions (e.g., load, bandwidth, interference, etc.) between the licensed and unlicensed band, initiate a signaling to switch between the two bands.
The patent application US 2015/0065152 A1 specifies an opportunistic carrier aggregation framework using both licensed and unlicensed bands. One or more metrics are used to switch on/off one or more bands from the unlicensed spectrum. The metrics can be cell loading, traffic type, QoS indication, number of users in the unlicensed band, available backhaul bandwidth, and interference from access points. The bands in the unlicensed bands are divided into preferred and non-preferred sets with more bias associated with the bands in the preferred set to be selected for communication.
Embodiments of the present invention are an improvement over prior art systems and methods.