As worldwide wireless traffic is expected to grow 25 times over the next five years, the trade association 4G Americas argues in a white paper titled, HSPA+LTE Carrier Aggregation,a potential new technique for further integrating HSPA and LTE spectrum.
The new feature, called HSPA+LTE carrier aggregation, is being considered at 3GPP for standards development.
The evolution of both HSPA+ and LTE standards has introduced aggregation of carriers for higher data rates, better load balancing and increased spectrum utilization, and since the dawn of LTE, the standard support for radio level interworking for HSPA and LTE radios has been included.
A natural continuation of such development is to tighten the interworking even further and introduce similar aggregation of carriers between the two radio access technologies.
The HSPA+LTE aggregation allows for transmitting data to one user simultaneously using both the HSPA and the LTE radios for maximal utilization of the available spectrum and the deployed equipment.
This is considered beneficial especially in the environment where the spectrum that needs to be shared between the two radio access technologies is not abundant, and the deployed HSPA and LTE capacities and user data rates suffer from spectrum crunch.
One example of such deployment is the 900 MHz for HSPA and the 800 MHz for LTE which are both seen attractive bands for building the coverage due to the low frequency but also suffer from very limited spectrum availability. With aggregation of the two bands it is possible to provide the high data rates expected from the LTE services while at the same time maintain coverage for the HSPA devices.