The active antenna unit is where massive MIMO actually lives. Array, transceivers, beamforming and the digital front end are fused into one unit on the mast — no coax feeders, far lower loss, and the per-element control that lets one site serve many users at once in the same spectrum.
A traditional site runs coax from a radio unit up to a passive antenna, losing power in the cable and limiting what beamforming can do. An active antenna unit puts the transceivers behind the array itself — one radio chain per element or sub-array — so beamforming is done where the antenna is, with no feeder loss.
That integration is what makes massive MIMO practical. With dozens of elements each driven by its own chain, the unit forms narrow beams and sends independent streams to several users on the same time and frequency — the capacity gain of MU-MIMO. The digital front end (CFR and DPD) sits in the same unit, keeping the many amplifiers efficient and within the spectral mask.
It connects to the baseband not by coax but by an O-RAN 7.2x eCPRI fronthaul over fibre, which is what lets the radio and the DU come from different vendors and sit in different places.
| Parameter | Detail |
|---|---|
| Configuration | 32T32R and 64T64R variants; sub-6 TDD bands per market |
| Beamforming | Digital / hybrid beamforming with per-element or per-subarray chains; MU-MIMO spatial multiplexing |
| Digital front end | Integrated CFR and DPD per path; calibration across elements for reciprocity |
| Fronthaul | O-RAN 7.2x split over eCPRI; block floating-point compression; PTP / SyncE timing |
| Integration | Array, transceivers, beamformer and DFE in one mast-mounted enclosure; no RF feeder cables |
| Thermal & power | Mast-top thermal design; the power and heat of many chains is the limiting constraint |
| Use | Macro and dense urban capacity layers; TDD mid-band massive MIMO |
The AAU is the capacity workhorse of a modern mid-band network — macro sites and dense urban layers where MU-MIMO multiplies spectral efficiency. It pairs with the O-RAN radio and distributed units in the portfolio and the fronthaul gateway that aggregates a cluster of them.
For a vendor building one, the antenna is the easy part; the RF chains, the per-slot beamforming compute, the fronthaul budget and the calibration that keeps reciprocity valid are the engineering.
We work on the AAU across the stack: the transceiver and front-end design per element, the beamforming and calibration, the CFR/DPD digital front end, the 7.2x fronthaul and timing, and the thermal design that ultimately sets output power. Deliverables span architecture, FPGA/SoC implementation, RF and OTA characterisation, and integration with the DU.
We can target 32T32R or 64T64R, the band plan, and the beamforming architecture against your capacity and power envelope.
A radio that integrates the antenna array, the transceivers, the beamforming and the digital front end into one mast-mounted unit, with no RF feeder cables. It is the physical form massive MIMO takes, connected to the baseband over an O-RAN 7.2x fronthaul.
A passive antenna is fed by coax from a separate radio, losing power in the cable and limiting beamforming. An AAU puts a transceiver chain behind each element or sub-array, so beamforming happens at the antenna with no feeder loss — which is what makes massive MIMO work.
64 transmit and 64 receive chains behind the array. More chains give finer beamforming and more spatial multiplexing (serving more users at once), at the cost of more converters, compute, power and heat. 32T32R is a lower-cost, lower-capacity point.
Over an O-RAN 7.2x eCPRI fronthaul on fibre, not coax. The split keeps low-PHY and RF in the AAU and the rest in the DU, with BFP compression and PTP/SyncE timing, and allows a multi-vendor deployment.
Not the antenna — the RF chains, the per-slot beamforming compute, the fronthaul bandwidth, the thermal design that limits output power, and the calibration that keeps transmit/receive reciprocity valid so the beams point true.
The technique it implements.
PRODUCTThe RU IP inside it.
PRODUCTCFR and DPD per path.
PRODUCTAggregates a cluster of them.
PRODUCTThe 7.2x fronthaul.
KNOWLEDGEKeeping the amplifiers clean.
The RF chains, per-slot beamforming, the fronthaul budget and the calibration that keeps reciprocity true are where an AAU is won. Tell us the band and the element count.