The Huawei RRU5904 and RRU3971 are both 4T4R remote radio units for the 1800 MHz and 2100 MHz bands, and both connect to a Huawei BBU over CPRI. The short answer: the RRU5904 is the newer, higher-power unit (4 x 60 W versus 4 x 40 W at 1800 MHz), carries more LTE carriers and adds NR FDD support on recent software, while the RRU3971 is smaller, lighter and well suited to existing LTE and GSM+LTE sites. This guide compares the two models using Huawei’s published technical specifications and explains which one fits your network.
Where each model sits in Huawei’s RRU range
The RRU3971 belongs to Huawei’s 3900-series radios used in DBS3900 distributed base stations, typically paired with a BBU3900 or BBU3910. The RRU5904 is part of the 5900 series that launched alongside the DBS5900 and BBU5900, and it also works with DBS3900 sites. Both are outdoor units rated IP65, run on -48 V DC and use the same 400 mm x 300 mm footprint, so they usually fit the same mounting positions on a pole or wall.
The differences show up in output power, carrier capacity, RAT support and the size of the unit’s heat sink.
RRU5904 vs RRU3971: specification comparison (1800 MHz)
The figures below come from Huawei’s RRU3971 Description and the RRU5904 Technical Specifications (V100R016C10). Values can change with hardware version and software release, so always confirm against the documentation for your own load.
| Item | RRU3971 (1800 MHz) | RRU5904 (1800 MHz) |
|---|---|---|
| TX/RX | 4T4R | 4T4R |
| TX / RX band | TX 1805–1880 MHz / RX 1710–1785 MHz | TX 1805–1880 MHz / RX 1710–1785 MHz |
| Instantaneous bandwidth (IBW) | 45 MHz | 45 MHz |
| Maximum output power | 4 x 40 W | 4 x 60 W |
| LTE FDD carriers | 2 | 3 |
| RATs (per Huawei docs) | LTE FDD, GSM+LTE multimode; NR as SUL on later releases | GSM, LTE FDD, NB-IoT, NR FDD, NR SUL |
| CPRI ports | 2, at 1.25 / 2.5 / 4.9 / 9.8 Gbit/s | 2, at 1.25 / 2.5 / 4.9 / 9.8 Gbit/s |
| Dimensions (H x W x D) | 400 x 300 x 100 mm (12 L) | 400 x 300 x 150 mm (18 L) |
| Weight | 15 kg | 22 kg |
| Power input | -48 V DC (-36 to -57 V DC) | -48 V DC (-36 to -57 V DC) |
| Operating temperature | -40°C to +55°C (no solar radiation) | -40°C to +55°C (no solar radiation) |
| Ingress protection | IP65 | IP65 |
Key differences explained
1. Output power and coverage
The RRU5904 delivers up to 4 x 60 W, against 4 x 40 W for the RRU3971 at 1800 MHz. In practice the extra power is useful in two situations: when a single radio must carry several carriers or several RATs at once (power is shared across carriers), and on rural or suburban sites where cell edge coverage matters. Huawei’s RRU3971 documentation shows that with two LTE carriers the power drops to 4 x 20 W per carrier, which illustrates how quickly a 160 W radio is divided once you add carriers.
2. Carrier capacity and RAT support
At 1800 MHz the RRU5904 supports up to 3 LTE FDD carriers, up to 8 GSM carriers, NB-IoT and, on V100R016C10 and later, NR FDD in Band n3. At 2100 MHz it supports UMTS (up to 8 carriers without MIMO, 4 with MIMO), LTE FDD and NR FDD in Band n1, with a 60 MHz IBW.
The RRU3971 at 1800 MHz is documented for LTE single mode with 2 carriers and 4×4 MIMO, and for GSM+LTE multimode. Huawei’s overview tables also list UMTS, LTE FDD and UMTS+LTE for the 2100 MHz version. If your plan includes NR FDD on the same radio, the RRU5904 is the safer choice.
3. Size, weight and installation
Both units share the 400 x 300 mm face, but the RRU5904 is 50 mm deeper and 7 kg heavier (22 kg versus 15 kg). The larger heat sink supports the higher output power. Check pole brackets, wind load and tower loading before replacing an RRU3971 with an RRU5904 on an existing structure. Huawei quotes a typical power consumption of 492 W for the RRU5904 at 25°C and 50% traffic load, so also confirm that the site’s DC power system and breakers have headroom.
4. CPRI and BBU connection
Both radios have two CPRI ports supporting 1.25, 2.5, 4.9 and 9.8 Gbit/s, and both support star, chain and dual-star topologies. Either can be connected to UBBP boards in a BBU3910 or Huawei BBU5900, subject to the software release. For LTE, Huawei documents a maximum distance from the BBU of 20 km or 40 km depending on the baseband board type. See our BBU5900 board compatibility guide for UBBP and UMPT details.
Which one should you choose?
- Choose the RRU3971 when you are replacing a failed unit on an existing DBS3900 LTE or GSM+LTE site, when tower loading is tight, or when 4 x 40 W is enough for your carrier plan. A like-for-like swap avoids re-planning power settings and mechanical work.
- Choose the RRU5904 when you need more carriers per radio, more output power for coverage, multi-RAT operation including NB-IoT, or a path to NR FDD on 1800 or 2100 MHz.
A common approach for operators maintaining older sites is to keep a pool of RRU3971 spares for direct replacement while deploying RRU5904 units on new or expanded sectors.
What to check when buying either model used
- Band variant. The model name alone is not enough. Confirm the frequency band on the label (for example 1800 MHz or 2100 MHz) and the BOM code, and match them to your licensed spectrum.
- Software support. Make sure your BBU software release supports the radio and the RATs you plan to run. NR FDD support on the RRU5904 depends on the release.
- Physical condition. Inspect the four RF connectors, CPRI ports and power connector for corrosion or damage, and check that the housing seals and heat sink fins are intact.
- RF performance. Ask for output power and VSWR results on all four transmit paths, plus an alarm check when connected to a BBU.
Our Huawei RRU testing checklist covers these steps in more detail.
Available models
We supply both models in the two most common bands:
You can browse the rest of our radio units and baseband boards in the Huawei category.
FAQ
Can an RRU5904 directly replace an RRU3971?
Electrically and logically, usually yes: both are 4T4R, use -48 V DC and connect to the BBU over CPRI. You need to confirm software support on the BBU, reconfigure the radio in the site configuration, and check that the mounting and tower loading can take the deeper, heavier RRU5904.
Do the RRU5904 and RRU3971 have the same IBW?
At 1800 MHz both have a 45 MHz instantaneous bandwidth. The RRU5904 2100 MHz version has a 60 MHz IBW, covering the full Band 1 downlink.
Does the RRU3971 support 5G NR?
Huawei’s later documentation lists NR only as SUL (supplementary uplink) for the RRU3971. For NR FDD carriers on 1800 or 2100 MHz, the RRU5904 is the appropriate model.
Which BBU do these radios work with?
Both work with Huawei DBS3900 and DBS5900 baseband units, such as the BBU3910 and BBU5900, through UBBP baseband boards, subject to the software release on site.
Order tested Huawei RRUs
Every unit we sell is functionally tested before shipment, and radio units such as the RRU5904 and RRU3971 are also VSWR tested. All items come with a 90-day warranty, and we ship worldwide in secure packaging. Contact us on WhatsApp at +86 187 3329 4669 or +86 139 3088 8705, email jack@telecombts.com, or use the form at https://telecombts.com/contact-us/ with your band, quantity and BBU type. We also buy surplus Huawei, Ericsson and Nokia equipment: see Sell Your Equipment.