Technical Description

The K-BOW system consists of the following nodes, which can be placed in a physically separated way:

Aggregation Layer

The Central Hub (C-Hub)

At the C-Hub, MNO base stations are connected to the K-BOW via standardised analogue interfaces. The band-selective front-end modules support three input ports per band and are available for multiple frequency bands. This variety of units provides the flexibility for operators to equip the C-Hub just with the bands to be used in the K-BOW system. Since the full spectrum of each band is supported, the C-Hub is ready to connect multiple operators as well as MIMO-capable Base Transceiver Stations (BTS). The C-Hub transforms the signals into a digital data stream. On the digital domain, the K-BOW system can access, condition and route every single subband within the K-BOW system. Via configuration, the desired signal mix is aggregated and forwarded in the system.

Distribution Layer

The Expansion Hub (E-Hub)

The digital signal covering a mobile bandwidth of 240 MHz spectrum per 10 Gbps optical link is forwarded to the E-Hub. The digital link allows distances of up to 20 km. Depending on the routing flexibility in a system, between 8 and 64 E-Hubs can be connected to the C-Hub layer. At the E-Hub, the signals are converted to analogue signals and then allocated to up to three sectors. This allocation can be changed remotely via the node manager or standardised SNMP integration to a legacy MNO OSS system.

Optimisation Layer

The Remote Unit (RU)

Each RU is equipped with band-selective transceivers and LTE MIMO transceivers. The K-BOW RUs also provide transparent IP connectivity with a throughput of up to 700 Mbps, which can be used for a sensor network, a small cell or WiFi access points. The K-BOW RUs are available as wall-mounted versions with integrated broadband antennas and also as a hidden ceiling-mounted version with an external antenna. Since each band is controlled separately, the output power per band can be adjusted according to the respective situation. This provides entirely new options for operators to optimise indoor signals by individually controlling the output power per band per RU and not within a DAS tree of connected antennas. The output power of the low-power RU is up to 22 dBm per band, which is sufficient to support multi-operator scenarios with typical power requirements.