Mastering Modern DAS Connectivity: The Role of the Point of Interconnection (POI)

In the rapidly evolving landscape of wireless communication, the demand for seamless, high-capacity in-building coverage (iDAS) has never been higher. As mobile users consume more data within stadiums, airports, shopping malls, and high-rise office buildings, the complexity of managing multiple cellular frequencies from different operators becomes a significant engineering challenge. At Hefei BRI Electronic & Technology Co., Ltd, we specialize in the high-performance RF passive components—including combiners, triplexers, and specialized point of interface in telecom—that bridge the gap between base stations and distribution networks.

The heart of a sophisticated Distributed Antenna System is the Point of Interconnection (POI). This article explores the critical role of the poi point of interconnect, its core applications, and the technical parameters that define a high-quality unit, specifically referencing our advanced 12-In-2-Out, Hexa Band POI .

What is a POI (Point of Interconnection) in Telecom?

A point of interconnection or point of interface in telecom serves as the vital hub where signals from multiple Base Transceiver Stations (BTS) or different service providers are combined and conditioned before being launched into the DAS distribution network. Without a poi point of interfac, each operator would require a separate antenna infrastructure, leading to massive hardware redundancy, increased costs, and physical clutter.

The POI functions as a multi-band combiner that handles high power levels, ensures high isolation between different frequency bands, and minimizes signal interference. By consolidating signals into a single output (or multiple balanced outputs), it allows for a unified infrastructure that supports 4G, 5G, and public safety bands simultaneously.

Applications of the Point of Interconnection

The poi point of interconnect is indispensable in neutral-host environments where multiple mobile network operators (MNOs) share a single DAS.

1. Large-Scale In-Building Systems (iDAS)

In venues like airports or convention centers, signals from various bands (700MHz to 3500MHz) must be unified. A POI allows these disparate frequencies to share the same fiber or coaxial distribution backbone.

2. Multi-Operator Neutral Host Environments

In many commercial buildings, the landlord provides a “neutral host” system. The POI acts as the interface where Operator A, Operator B, and Operator C plug in their respective base stations. It ensures that Operator A’s signal does not bleed into or interfere with Operator B’s equipment.

3. Transitioning to 5G

Modern systems must accommodate legacy 4G LTE while integrating new sub-6GHz 5G bands. High-performance POIs, are designed to support bands up to 3800MHz, ensuring that existing DAS infrastructure remains future-proof.

Technical Deep-Dive: Key Parameters for POI Performance

When evaluating a point of interconnection, several electrical and mechanical specifications are critical to maintaining network health. Based on the specifications found in POI.jpg, let’s examine the essential parameters.

1. Frequency Band Coverage

A versatile point of interface in telecom must support a wide range of frequencies. our Hexa Band POI covers the following critical bands:

700 MHz: (703–733 & 758–788 MHz)
800–900 MHz: (791–862 & 880–960 MHz)
1800 MHz: (1710–1880 MHz)
2100 MHz: (1920–2170 MHz)
2600 MHz: (2490–2690 MHz)
3500 MHz: (3300–3800 MHz)

2. Passive Intermodulation (PIM)

PIM is perhaps the most critical metric for any passive RF component. It refers to unwanted interference signals created when two or more high-power tones interact in non-linear components. Our POI features a 3rd PIM rating of $\leq -153$ dBc @ 2x43dBm, ensuring that the noise floor remains low and data speeds remain high.

3. Isolation

Isolation prevents signals from one port from interfering with another.

Same Band Isolation: ≥ $\geq 23$ dB
Cross Band Isolation: ≥ $\geq 30$ dB for 700/800-900M bands, and ≥ $\geq 50$ dB for other bands.
High isolation is mandatory to protect sensitive BTS equipment from high-power signals generated by adjacent transmitters.

4. Power Handling

Because POIs are directly connected to base stations, they must withstand significant input power. The unit is rated for 200W Average Input, allowing it to handle high-traffic environments without thermal degradation.

5. Insertion Loss

Minimizing signal loss is vital to ensure maximum coverage at the antenna end. Our POI maintains an Insertion Loss of ≤ $\leq 6$ dB, a highly competitive figure for a complex 12-in-2-out Hexa Band configuration.

Mechanical Integrity and Design

Reliability extends beyond electrical specs. As noted in the POI.jpg mechanical data section:

Dimensions: $482 \times 320 \times 178$ mm, designed for standard rack mounting.
Connectors: Utilizes 4.3-10 Female connectors (12 input, 2 output), which are the industry standard for low-PIM performance and robust physical connection.
Environmental Protection: With an IP65 rating, this unit is protected against dust and low-pressure water jets, making it suitable for varying installation environments.
Operating Temperature: $-10$ to $+65$ °C, ensuring stable performance in non-climate-controlled equipment rooms.

Conclusion

The poi point of interconnect is the silent engine of modern in-building wireless systems. By meticulously managing cross-band isolation, minimizing PIM, and supporting the full spectrum of cellular bands—including 5G—Hefei BRI’s POI solutions provide the reliability that operators and building owners demand.