Many legacy systems need an architecture upgrade to support 5G MIMO
May require new fiber routes
Longer construction windows
Additional site coordination
After a site survey and link-budget review, the solution can:
Reuse existing infrastructure where technical and commercial conditions support it
Limit new cabling and property work at suitable retrofit sites
Minimized site disruption accelerates approvals
Band, duplex mode, RRU, passive network, and operator requirements are reviewed for each project
Monitoring, alarms, remote configuration, and upgrade functions depend on the deployed version
| Passive DAS System | RFCOM’s 5G Coverage System | Optic Digital DAS System | |
|---|---|---|---|
| Description | Using two channels of coaxial cables | Replace some parts of the existing DAS to Implement 5G MIMO 2T2R/4T4R | New pRRU distribution system |
| Construction period | Long | Short | Long |
| Difficulty in construction | High | Low | High |
| Difficulty in property coordination | High | Low | High |
| Antenna monitoring | No | Yes | Yes |
| 2T2R download rate | 500M~600M | 600M~700M | 600M~700M |
| Cost per square meter | 1USD (Assuming) | 1USD | 4-5USD |
| Power consumption | Low | Low | High |
It upgrades the passive coaxial DAS already installed in a venue to a 5G MIMO system, without pulling new cable. A Master Unit and a 5G combiner are added in the equipment room, the existing couplers are replaced with DC feeder couplers, and the passive antennas are replaced with active Remote Units. The coaxial trunk, the riser routes, the splitters and the antenna positions are all reused.
The two MIMO branches from the 5G RRU enter the Master Unit. One is down-converted to an intermediate frequency; the other passes through at its original frequency. Both are combined with the existing 2G, 3G and 4G services and travel over the same coaxial cable. At the Remote Unit the shifted branch is converted back to its original frequency, and both branches are radiated together — producing two genuine spatial streams at that antenna point.
Where the venue has a dual-cable DAS, 4T4R is achievable.
The Master Unit feeds DC power to the Remote Units over the coaxial cable itself. No separate mains connection is needed at any antenna point.
This is one of the fundamental differences from a fiber active DAS. There, every remote point needs its own power feed — a large part of the cost, and the main reason deployment takes months and landlord negotiations are difficult. We carry the power on the cable that is already in the ceiling, and those problems disappear.
Three things, at every site: a Master Unit and a 5G combiner are added in the equipment room; couplers are replaced with DC feeder couplers; passive antennas are replaced with Remote Units.
What the site survey determines: how many of each, and whether individual splitters, connectors or feeder sections need replacing because they do not meet the required frequency range, DC path or power handling.
No. The frequency shift is applied to only one of the 5G branches. 2G, 3G and 4G stay on their original RF path, unchanged, and there is no interruption during the work.
The equipment is full-band. For 5G this is typically the 3.5 GHz band (n78, 3300–3700 MHz), but the frequency-shift technique is not limited to 3.5 GHz — 2.6 GHz and other bands can be used for MIMO in the same way.
Existing 2G, 3G and 4G services pass through on the same cable, untouched.
A fiber active DAS is a rebuild: new fiber and a new mains feed at every remote point, on a schedule measured in months. This is an upgrade: the existing coaxial plant is reused, DC power reaches the Remote Units over that same coaxial cable, and no new RF cabling or local power is needed at any antenna point.
Deployment therefore falls from months to days, and both cost and total site power drop sharply. The trade-off is throughput slightly below a fiber active DAS.
Days, not months.
No interruption. The work replaces equipment at the existing antenna positions in the ceiling, plus the installation in the equipment room. Risers and walls are untouched, and there are no civil works.
There is one test: whether the venue has an existing coaxial DAS that can be reused.
Our value comes from reuse. A newly built venue that has never had indoor coverage — a new airport, a new shopping centre — is not a case for this solution and should be built new.
Conversely, any venue with a passive DAS installed during the 2G, 3G or 4G era — airport, shopping centre, hospital or office tower alike — is a candidate.
Yes. High-traffic floors or weak-coverage zones can be done first, with the rest left on passive coverage. Each retained branch still has to be checked for frequency compatibility, DC isolation and its effect on the link budget.
Up to 60 in theory. In practice, allowing for link loss and power delivery, around 30 is the sensible figure.
The Remote Unit provides power compensation for the feeder loss on the pass-through branch.
This is also why the Remote Units have to be replaced rather than simply adding equipment in the equipment room: a passive antenna has no way to compensate, so whatever is lost is lost.
Automatic power balancing monitors the level of the pass-through and restored branches and adjusts the frequency-shifted path. Dynamic output-power compensation offsets the difference in feeder and passive-component loss between antenna points.
The system degrades; it does not go dark.
This follows from the architecture: neither the legacy services nor the pass-through 5G branch passes through the frequency-shift path.
By contrast, a fiber active DAS is fully digital — when a remote unit fails, every service at that point goes down with it.
Device inventory, Master and Remote Unit status, output power and MIMO balance monitoring, topology and site map views, alarms and logs, remote gain adjustment and on/off control.
It supports SNMP and can be integrated into an operator's or tower company's own NMS — there is no need to maintain a separate platform for this equipment.
Remote Unit: below 4 W in energy-saving mode, below 10 W with MIMO active. Master Unit: below 20 W at full load. A 6,000 m² site draws around 2,300 W in total, against roughly 7,500 W for a fiber active DAS in the same venue — a difference that usually lands on the property owner's electricity bill.
The frequency-shift channel is traffic aware: below a configurable threshold it powers down; above it, it switches back on and MIMO is restored.
Yes. Each operator only needs to connect its own RRU; the equipment is full-band, so a single system can carry several operators at once.
This suits indoor systems run by neutral hosts particularly well — one upgrade, shared by several operators.
Against a fiber active DAS: CAPEX reduced by approximately 70%, power consumption reduced by approximately 60%, and deployment time reduced from months to days.
The existing DAS schematic, feeder routes and lengths, cable and passive-component models, antenna layout, building drawings, services in use, target 5G bands and bandwidth, RRU configuration, site photographs, existing RF measurements, coverage objectives and acceptance criteria.
Before-and-after testing should use the same locations and methods, normally comparing RSRP, SINR, uplink and downlink throughput, MIMO branch balance, alarms and service continuity.
