RF
RU
10Radio models (2 MMU · 8 RRU)
32T32RPeak T/R (Massive MIMO)
192Antenna elements (MT3212)
16LMax DL MIMO layers
25 GbpsFronthaul (MMU / 8T8R)
Anatomy of a Samsung radio — what sits between the antenna and the DU
A radio (RU) is an integrated RF module: antenna ports → filter/duplexer → power amplifier (Tx) & low-noise amplifier (Rx) → transceiver (RF chains, DAC/ADC) → optical fronthaul to the baseband. The number of independent Tx/Rx chains — the T/R configuration — is the single most important number: it sets how many MIMO layers and how much beamforming the cell can do.
RRU signal chain — antenna → RF front-end → transceiver → CPRI to DUOption 8 split
RF/optical pathRRUs use Option 8 — all PHY stays in the DU; the RU carries only RF over CPRI/eCPRI.
Massive MIMO Unit (MMU) — antenna array → digital beamforming → 32 chainsOption 7-2a split
32 parallel RF chainsThe MMU carries Low-PHY (PHY-L) on-board — a Split Option 7-2a radio, not a plain RRU.
Reading the model number — the naming convention in this portfolio
MT
Massive-MIMO Unit (TDD).
MT3212-78B, MT3234-78A — 32T32R, n78.RT
RRU, TDD band.
RT8813-78A (n78), RT4436/4448-40A (n40/B40).RF
RRU, FDD band.
RF2236-08A (B8), RF44xx-03x (B3), RF6602-08A (B8/n8).i
The suffix encodes band & branches — e.g.
-78 = 3.5 GHz (n78), -40 = 2.3 GHz (B40/n40), -08/-03 = 900/1800 MHz; the trailing letter is the hardware revision (A, B). Pattern observed across this portfolio. The T/R configuration ladder — from refarm RRU to Massive MIMO
More Tx/Rx chains → more layers → more beamforming2T2R → 32T32R
The full portfolio matrix — every radio, side by side
Samsung radio portfolio (from Product Specifications, Airtel EN)
| Model | Type | Band / Duplex | T/R | Channel BW | Output power | Fronthaul | Power draw | Dim W×H×D (mm) | Weight |
|---|---|---|---|---|---|---|---|---|---|
| MT3212-78BMMU | Massive MIMO | n78 TDD | 32T32R | 100 / 200 MHz | 192 AE array | 25G×2 CPRI | 996 W @100% | 400×700×127 | 23 kg |
| MT3234-78AMMU | Massive MIMO | n78 TDD | 32T32R | 100 MHz | 128 AE array | 25G×2 CPRI | 761 W @100% | 400×500×108 | 14.4 kg |
| RT8813-78ARRU | RRU | n78 TDD | 8T8R | 100 / 30+40 MHz | 40 W/path (320 W) | 25G×2 CPRI | 990 W @100% | 350×450×127 | 20 kg |
| RF6602-08ARRU | Multi-RAT RRU | B8·n8 FDD | 6T6R | 6CC 5–20 MHz +GSM | 80 W/path | 10G×2 C/eCPRI | 1210 W @100% | 370×460×176 | 29 kg |
| RF4480-03BRRU | Multi-RAT RRU | B3 FDD | 4T4R | 2CC 5–20 MHz +GSM | 80 W/path | 5/10G×2 C/eCPRI | 780 W @100% | 350×450×95 | 15.5 kg |
| RF4455-03ARRU | RRU | B3 FDD | 4T4R | 20 MHz 1CC | 40 W/path | CPRI | 500 W @100% | 320×400×117 | 15 kg |
| RF4460-03ARRU | RRU | B3 FDD | 4T4R | 20 MHz 2CC | 20 W/path | 5/10G×2 | 345 W @100% | 320×320×115 | 12 kg |
| RF2236-08ARRU | Multi-RAT RRU | B8 FDD | 2T2R | 2CC 3–20 MHz | 80 W/path | 5/10G×2 C/eCPRI | 490 W @100% | 320×320×142 | 14.5 kg |
| RT4436-40ARRU | RRU | B40·n40 TDD | 4T4R | 2CC 10/20 MHz | 40 W/path | 10G×2 CPRI | 470 W @100% | 320×400×123 | 17.8 kg |
| RT4448-40ARRU | RRU | B40·n40 TDD | 4T4R | 2CC 10/15/20 MHz | 40 W/path | 10G×2 CPRI | 390 W @100% | 320×320×95 | 10 kg |
Output power shown per Tx path; total ≈ per-path × T. Power draw = typical @100% load, 35 °C. All units: −48 V DC, natural-convection cooling, IEC 60529 IP65, operating −40 °C to +55 °C.
Per-radio specification cards
Massive MIMOMT3212-78B32T32R
Band / duplexn78 · TDD (3.5 GHz)
Antenna2V16H · 192 AE
MIMO capacityDL 16L · UL 8RX (4L)
Channel BW100 / 200 MHz (1–2 CC)
Fronthaul25 Gbps ×2 · CPRI · 20 km
SplitDL 7-2a/7-2aM · UL 7-2a
Power draw638 / 996 / 1046 W
Dim · weight400×700×127 · 23 kg
Massive MIMOMT3234-78A32T32R
Band / duplexn78 · TDD (3.5 GHz)
Antenna2V16H · 128 AE (4×1 sub-array)
MIMO capacityDL 16L · UL 8RX (4L)
Channel BW100 MHz
Fronthaul25 Gbps ×2 · CPRI · 20 km
Power draw761 W @100%, 35 °C
Dim · weight400×500×108 · 14.4 kg
Notelighter / lower-power MMU
RRU · n78RT8813-78A8T8R
Band / duplexn78 · TDD (3.5 GHz)
Channel BW100 MHz 1CC / 30+40 MHz 2CC
Output power40 W/path (320 W total)
Antenna portsANT0–7 · 4.3-10 × 8
Fronthaul25 Gbps ×2 · Duplex/Bi-di
RETAISG 2.0
Power drawTyp 990 W @100%
Dim · weight350×450×127 · 20 kg
Multi-RAT RRU · 900RF6602-08A6T6R
Band / duplexB8, n8 · FDD (900 MHz)
Channel BW6CC 5/10/15/20 MHz + GSM 18TRX
Output power80 W/path
Fronthaul10 Gbps ×2 · CPRI/eCPRI
Multi-RATGSM + LTE + NR
Power draw1210 W @100%
Dim · weight370×460×176 · 29 kg
MiscSpectrum analyzer (TX/RX)
Multi-RAT RRU · 1800RF4480-03B4T4R
Band / duplexB3 · FDD (1.8 GHz)
Channel BW2CC 5/10/15/20 MHz + GSM 8TRX
Output power80 W/path
Fronthaul5/10 Gbps ×2 · CPRI/eCPRI
DSSL0 LTE or LTE/NR DSS [SVR25A]
Power draw780 W @100%
Dim · weight350×450×95 · 15.5 kg
RRU · 1800RF4455-03A4T4R
Band / duplexB3 · FDD (1.8 GHz)
Channel BW20 MHz 1 carrier
Output power40 W/path
FronthaulCPRI
Power draw500 W @100%, 35 °C
Dim · weight320×400×117 · 15 kg
CoolingNatural convection
RRU · 1800 compactRF4460-03A4T4R
Band / duplexB3 · FDD (1.8 GHz)
Channel BW20 MHz (up to 2CC)
Output power20 W/path
Fronthaul5/10 Gbps ×2
Power draw345 W @100%, 35 °C
Dim · weight320×320×115 · 12 kg
Notesmallest / lightest B3 unit
Multi-RAT RRU · 900RF2236-08A2T2R
Band / duplexB8 · FDD (900 MHz)
Channel BW2CC 3/5/10/15/20 MHz
Output power80 W/path
Antenna portsANT0–1 · 4.3-10
Fronthaul5/10 Gbps ×2 · CPRI/eCPRI
Power draw490 W @100%
Dim · weight320×320×142 · 14.5 kg
RRU · 2300RT4436-40A4T4R
Band / duplexB40, n40 · TDD (2.3 GHz)
Channel BW2CC 10/20 MHz
Output power40 W/path
Antenna portsANT 0/1/2/3 · 4.3-10
Fronthaul10 Gbps ×2 · 20 km
Power draw470 W @100%
Dim · weight320×400×123 · 17.8 kg
RRU · 2300 compactRT4448-40A4T4R
Band / duplexB40, n40 · TDD (2.3 GHz)
Channel BW2CC 10/15/20 MHz
Output power40 W/path
Antenna portsANT 0/1/2/3 · 4.3-10
Fronthaul10 Gbps ×2 · 20 km
Power draw390 W @100%
Dim · weight9.73 L · 320×320×95 · 10 kg
Connectors, ports & cabling — the "wire" side of every radio
Four cable types land on every Samsung radio: RF antenna (4.3-10 connectors), optical fronthaul (SFP/SFP+ modules carrying CPRI/eCPRI to the DU/CDU), DC power (−48 V), and the RET control line (AISG, for remote electrical tilt). The 8T8R RT8813 adds a dedicated beamforming calibration port.
What plugs into a radio — the four interfacesantenna · optic · power · RET
RF / optical power / control4.3-10 = RF antenna connector · SFP/SFP+ = optic fronthaul module · AISG = tilt control.
Connectors & cabling per radio (from Product Specifications)
| Model | Antenna port | Fronthaul optic | DC power connector | RET (AISG) |
|---|---|---|---|---|
| MT3212-78B | Integrated array | SFP GUSPAP screw · CPRI 25G×2 · SM 20km | Johnson Push-Pull (40A) | Circular 8-pin · AISG 2.2 |
| MT3234-78A | Integrated array | CPRI 25G×2 · 20km | −48 V DC | AISG 2.2 |
| RT8813-78A | 4.3-10 female ×8 + CAL port | SFP · CPRI 25G×2 · Duplex/Bi-di | Inner 2-pin circular + outer push-pull | Screw 8-pin circular · AISG |
| RF6602-08A | 4.3-10 ×6 | SFP+ · C/eCPRI 10G×2 | −48 V DC | AISG 2.0 |
| RF4480-03B | 4.3-10 ×4 (ANT0–3) | SFP+ · C/eCPRI 5/10G×2 | −48 V DC | AISG 2.0 |
| RF4455-03A | 4.3-10 ×4 | SFP · CPRI | −48 V DC | AISG 2.0 |
| RF4460-03A | 4.3-10 ×4 | SFP+ · 5/10G×2 | −48 V DC | AISG 2.0 |
| RF2236-08A | 4.3-10 ×2 (ANT0–1) | SFP+ · C/eCPRI 5/10G×2 | −48 V DC | AISG 2.0 |
| RT4436-40A | 4.3-10 ×4 (ANT0–3) | Screw SFP/SFP+ · CPRI 5/10G | Screw 2-pin circular | Screw 8-pin circular · AISG 2.0 |
| RT4448-40A | 4.3-10 ×4 (ANT0–3) | Screw SFP/SFP+ · CPRI 5/10G | Screw 2-pin circular | Screw 8-pin circular · AISG 2.0 |
4.3-10 · RF antennaSFP / SFP+ · optic moduleCPRI / eCPRI · fronthaul−48 V DC · telecom powerAISG 2.0/2.2 · RET tiltCAL · BF calibration (RT8813)
i
All units share −48 V DC input, natural-convection cooling and IP65; LEDs report
SYS · OPT · ANT · RET status. On multi-RAT RRUs, one optic (L0) carries LTE/NR and a second (L1) carries GSM. Radio-port explorer — every connector on every radio ◆ from the Product Specifications
Pick a radio to see its real faceplate layout. Click any port for its exact connector type and function — the same connector-exact view as the baseband card explorer. Note the key split: an RRU has external ANT ports (one 4.3-10 per T/R path); an MMU has no antenna ports at all — the array is integrated, so it exposes only power, optic, ALD and ground.
RF antennaCPRI/eCPRI fronthaulDC powerRET / ALD (tilt)CalibrationGround / LED
Click a port above to see its connector type and function…
The RF chain — how a signal becomes a radio wave (Tx & Rx path)
Inside every radio is the same signal chain (from the Product-Spec block diagrams). Downlink (Tx): the DU's Digital I/Q arrives over optic → the RU turns numbers into an amplified RF wave. Uplink (Rx): the antenna's faint RF is amplified, digitised and sent back as I/Q. This is the "muscle" the baseband drives.
Tx path (downlink) — Digital I/Q → RF wavefrom DU to antenna
Optic O/E
CPRI in from DU
CPRI Fmt
deframe I/Q
DUC → DAC
digital→analog
Up-Conv
to RF freq
PA
power amp
Filter
TDD dup.
Antenna
RF wave out
Rx path (uplink) — RF wave → Digital I/Qantenna back to DU
Antenna
faint RF in
Filter
band select
LNA
low-noise amp
Down-Conv
to baseband
ADC → DDC
analog→digital
CPRI Fmt
frame I/Q
Optic E/O
CPRI out to DU
Each T/R path is one full chain — a 4T4R radio has 4, an 8T8R has 8, a 32T32R MMU has 32 (feeding the 192-element array).
≡
Where the RF-path faults live — PA problems → the
ANT LED (VSWR) + per-path carrier-rssi/temperature (AU MO); LNA / Rx problems → high per-path RSSI + the −62 dBm alarm; filter / antenna problems → VSWR alarm (reflected power). The CAL port on Massive MIMO keeps all 32 chains phase-aligned so the beams actually form — a calibration fault collapses beamforming gain even with every PA healthy. Reading the radio faceplate — the SYS · OPT · ANT · RET LED decoder
On a tower climb (or from photos), the four LEDs tell you the radio's health before you touch the EMS. Exact states from the Product-Spec LED tables:
Radio LED states (RRU/MMU)
| LED | Green blinking | Green on | Red blinking | Red on | Off |
|---|---|---|---|---|---|
| SYS (system) | ✅ Normal — no path alarm | Standby — ready, no path active | Imperfect — 1 path alarmed, ≥1 OK | Abnormal — all paths down / CPRI not set up / init | No power |
| OPT (optical) | ✅ Normal — link OK | No optical module inserted | 1 port RX-LOS / Tx-fault, ≥1 OK | RX-LOS or Tx-fault on all ports | No power |
| ANT (VSWR) | ✅ Normal — no VSWR alarm | No RF output (PA disabled) | 1 path VSWR major, ≥1 OK | VSWR major alarm on all paths | No power |
| RET (tilt) | ✅ RET OK & receiving data | RET power OK but no data 180 s | Reserved | RET power fails | No power |
!
Field reading —
SYS red-on = the radio is effectively dead (all paths down or CPRI never came up — check the optic first). ANT red = a VSWR / return-loss problem — feeder, connector or antenna (a PIM/water-ingress classic), not a parameter. OPT green-on (steady, not blinking) is a trap: it means no SFP inserted, not "good". Only green-blinking is healthy on SYS/OPT/ANT. Massive MIMO deep-dive — the antenna array & beamforming
The MMU integrates the antenna array with the transceivers. MT3212-78B carries a 2V16H arrangement of 192 antenna elements driven by 32 Tx/Rx chains; MT3234-78A is a lighter 128-AE variant (4×1 sub-array). The array forms narrow beams (digital beamforming) so the cell can serve up to 16 DL layers and 8 UL receive branches (4 layers) simultaneously — the capacity multiplier a plain 4T4R RRU can never reach.
2V16H arrangement192 AE (MT3212)128 AE (MT3234)DL 16 layersUL 8RX / 4 layersDigital beamforming
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Why this matters for optimization — beamforming gain and layer count are set by the hardware; your parameter tuning (RI/CQI reporting, SU/MU-MIMO thresholds, beam-management) only decides how well the cell exploits the array. Days 4 (Throughput) and 3 (Mobility/beam) tune inside this envelope.
Fronthaul & functional split — CPRI vs eCPRI, Option 7-2a vs Option 8
Fronthaul by radio class
| Radio class | Functional split | Interface | Rate · reach |
|---|---|---|---|
| Massive MIMO (MT3212 / MT3234) | Option 7-2a / 7-2aM (Low-PHY on-board) | CPRI | 25 Gbps ×2 · 20 km |
| 8T8R n78 RRU (RT8813) | Option 8 (all PHY in DU) | CPRI | 25 Gbps ×2 · 20 km |
| Multi-RAT RRU (RF6602 / RT44xx) | Option 8 | CPRI / eCPRI | 10 Gbps ×2 · 20 km |
| FDD RRU (RF2236 / RF44xx) | Option 8 | CPRI / eCPRI | 5 / 10 Gbps ×2 · 20 km |
A plain RRU keeps the whole physical layer in the DU (Split Option 8) and ships raw IQ over CPRI. A Massive MIMO Unit pulls Low-PHY (PHY-L) into the radio (Split Option 7-2a), which is what keeps the 32-chain fronthaul down to two 25 Gbps links instead of an impossible raw-IQ rate. On multi-RAT units, one optic (L0) carries LTE/NR (CPRI) and a second (L1) carries GSM (eCPRI).
The radio in software — the real AU managed-object tree ◆ 5G AU Parameter Description SVR25B v2.0 · 1,985 params
Everything on this page so far is sheet metal. This is how the gNB actually sees and controls a radio: the hardware-management/radio-unit/radio-unit-info subtree. Every value below is verbatim from the AU Parameter Description SVR25B — the radio-unit document that only became readable in this release set.
Radio identity & RF geometry — …/radio-unit/radio-unit-info
| Parameter | Range | Default | What it does for optimization |
|---|---|---|---|
unit-type / board-type | lru · e.g. g7ra-e00 | lru | the RU as the DU inventories it — board-type identifies the exact product build |
electrical-tilt | −40..40 | 0 | e-tilt lives in the RU MO — coverage/overshoot fixes are a config write, not (only) a RET motor |
start-frequency / rf-lo-frequency | 0..3,920,000 · 0..45,000,000 | 2,750,000 · 0 | the RF window the unit is tuned into (kHz) — must match the carrier plan |
auto-gps-flag + lat/long/height | off | on · strings | on | the RU self-reports its geolocation — feeds positioning & site audits |
number-of-carrier | 0..255 | — | how many carriers this unit currently runs (read-only state) |
operational-state / firmware-mode | disabled|enabled|… · user|factory | — | the health flags your scripts poll before blaming parameters |
Per-carrier control — …/radio-unit-info/carrier-control-info (carrier-index 0..7)
| Parameter | Range | Default | What it does for optimization |
|---|---|---|---|
dl-max-tx-power | −50..600 (0.1 dB steps) | 170 | the per-carrier power knob — coverage trims and energy saving act here, per carrier not per radio |
tx-attenuation | 0..100 (0.1 dB) | 0 | fine output-power backoff without re-declaring the carrier |
rssi-high-alarm-threshold | −720..−620 = −72.0..−62.0 dBm | −620 | the UL-interference alarm line — external interference watch starts at this MO, not at a counter |
rssi-low-alarm-threshold | −1280..0 = down to −124+ dBm | −1240 | dead-receiver detection (RSSI too low = path/feeder fault) |
current-tx-nr-arfcn / current-rx-nr-arfcn | read-only | — | the live NR-ARFCN per carrier — cross-check against the band map page |
cell-number / current-carrier-bandwidth | −1..7 · read-only | −1 | which DU cell rides this carrier and at what BW |
Per-path control & energy saving — …/radio-unit-info/path-control (path 0..3) + radio-sleep-mode
| Parameter | Range | Default | What it does for optimization |
|---|---|---|---|
path-switch | user-disable | user-enable | digital-unit-… | digital-unit-enable | administratively kill/restore a single Tx/Rx chain (suspected PA fault isolation) |
current-amp-state / temperature | read-only · −40..100 °C | — | PA health + thermal per path — read this before believing a coverage complaint |
path-energy-saving-state | disable | enable | enable | per-path ES is ON by default — remember it when hunting mysterious off-peak UL SINR shifts |
tx-carrier-switch / rx-carrier-switch | disable | enable | enable | carrier×path granularity — a carrier can be muted on one path only |
carrier-rssi (per path×carrier) | read-only, 0.1 dBm | — | the per-path UL noise view — path imbalance = feeder/antenna problem, not a parameter problem |
radio-sleep-mode-switch | none | deep-sleep | deep-sleep-by-es… | none | whole-radio deep sleep for energy saving windows |
energy-saving-radio-sleep-mode-switch | off | on | off | lets the ES feature drive sleep automatically |
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Why this tree matters — three classic field cases resolve here, not in cell parameters: (1) overshoot →
electrical-tilt per RU; (2) external UL interference → per-path carrier-rssi + the −62 dBm alarm threshold tell you which sector face and which path; (3) off-peak KPI oddities → check path-energy-saving-state (default enable) and sleep modes before opening a trouble ticket. Band → radio deployment map — which radio for which layer
Choosing the radio by band & role
| Band | Freq · duplex | Role | Radios in this portfolio |
|---|---|---|---|
B8 / n8 | 900 MHz · FDD | Wide-area coverage, GSM refarm | RF2236-08A (2T2R) · RF6602-08A (6T6R) |
B3 | 1800 MHz · FDD | Coverage + capacity, DSS | RF4455 · RF4460 · RF4480-03x (4T4R) |
B40 / n40 | 2300 MHz · TDD | TDD capacity | RT4436-40A · RT4448-40A (4T4R) |
n78 | 3500 MHz · TDD | 5G mid-band capacity | RT8813-78A (8T8R) · MT3212 / MT3234 (32T32R) |
n28 | 700 MHz · FDD | 5G coverage layer | (band in scope · dedicated radio not in this spec set) |
Radios are the envelope — everything else optimizes inside it.
The band, duplex, T/R chains, antenna array and output power fix the ceiling. From Day 2 onward, every golden-parameter change works within the limits these radios set. Next in 1.1: the baseband (CDU + CU/DU split) that drives them.