Verizon is already looking ahead to five-channel carrier aggregation (5CA) as it forges ahead with deployment of gigabit LTE technologies.
A company representative told Mobile World Live Verizon is planning to use a combination of higher level MIMO, 256QAM and carrier aggregation to hit the gigabit mark on its network. However, she said the number of aggregated channels will depend on the spectrum resources available. Some areas will require a little extra punch from unlicensed airwaves via the use of Licensed Assisted Access (LAA) technology.
“Everywhere we have three channels of owned spectrum, we’ve aggregated those,” the representative said: “We have two [channels aggregated] everywhere, and the places where we have three bands of spectrum, those are aggregated. So it’s really just a matter of where do we want to employ LAA and aggregate that shared spectrum now.”
“It will absolutely be based on need. There are just some places where LAA is not needed. It also is very much based on where the spectrum is and what we need to aggregate between our own spectrum and shared spectrum,” she continued.
The representative indicated deployments of four carrier aggregation with LAA, 4×4 MIMO and 256QAM are “happening now” where they’re needed in the network. Rollouts are “well underway”, she said, but added the fourth quarter will be a “big quarter for us to continue” deploying those technologies. Verizon already has LTE-U – a cousin of LAA – running in “some places” on its network and is upgrading those locations to LAA via a software update, the representative said.
Verizon is also looking ahead to 5CA, and is currently testing the technology in the lab the representative explained. For the operator, 5CA is a matter of incorporating one more band of shared spectrum in a manner similar to 4CA with LAA, she said.
Hitting the gigabit mark
Verizon completed gigabit LTE tests alongside Ericsson and Qualcomm using both 3CA of owned spectrum and 4CA using an additional channel of unlicensed spectrum through LAA technology. The latter test was conducted in Florida and achieved a peak speed of 953Mb/s. The former lab test used three aggregated 20MHz channels of licensed spectrum to squeak past the gigabit speed mark.
Like Verizon, T-Mobile was also able to cross the gigabit barrier in lab tests using just 3CA, 4×4 MIMO and 256QAM to hit 1.175Gb/s. Those experiments were completed alongside Nokia and Qualcomm using the Finnish vendor’s 4.9G network and AirScale Base station with a test device running on the latter’s Snapdragon X20 LTE modem.
AT&T and Sprint have both also revealed work on 4CA. In a July blog post, Sprint CTO John Saw said the operator was “preparing” for 4CA. At Mobile World Congress Americas earlier this month, though, the focus appeared to be more on impending deployments of 64×64 massive MIMO.
Early this year AT&T’s VP of RAN and Device Design, Gordon Mansfield, indicated the operator was “actively testing” 4CA. AT&T’s 5G Evolution plan calls for the operator to implement carrier aggregation and LAA technology to hit gigabit speeds by the end of this year.