Reliable public safety radio communications are vital in today’s emergency services operation, from dispatch to mission critical situations, and from voice only capabilities to voice and data.
Public safety communications have evolved from fire call boxes, analog land mobile radios (LMR) to digital LMRs and trunked radio systems. This evolution was mainly driven by technological advancements and the need for higher reliability. With the usage of higher frequency bands, and with more complex building environments such as dense building materials and energy efficient windows, an evolution in the in-building public safety infrastructure is also required to allow two-way radios or trunked radio systems to work seamlessly and reliably inside buildings and in underground tunnels, subways or mines.
Introducing Dali Matrix® Public Safety (PS) – the next generation all-digital Distributed Antenna System (DAS) to meet the stringent requirements of reliability and the evolving needs and requirements of public safety including broadband, LTE and FirstNet.
Dali Matrix® PS is the next generation all-digital DAS which transcends the traditional RF over fiber analog DAS and Bi-Directional Amplifiers (BDAs) for in-building public safety coverage. With its digital signal processing, it ensures that there’s minimal noise interference and signal degradation over the optical transport, thus, contributing to lower noise floor rise at the RF source and ultimately providing higher quality and reliability of radio communications.
Matrix PS is a simple, modular, two-tier architecture that consists of the hdHost™ PS and the medium power remote radio unit,
hd37™ PS. With its modular architecture, it provides great design flexibility to accommodate expansion and upgrades, and effective system redundancy configurations. Matrix PS is also a fully software configurable platform which enables channelization, upgrades and reconfiguration to be done remotely using software control and monitoring applications via the graphical user interface (GUI).
• Simple two-tier architecture
• Monitoring and control can be performed locally and remotely via software
• Single optical fiber with throughput of 10 Gb/s
• Up to 320 MHz of aggregated RF bandwidth per wavelength
• Supports P25 Phase I and II, TETRA & Tetrapol, and is FirstNet/LTE ready
• Accommodates 1 Gb/s or higher IP backhaul
• Integrated indoor and outdoor platform
• Supports base station and/or off-the-air RF feeds
• Provides secured/scrambled data transport
• Built-in software based spectrum analyzer
• Compliant to NFPA and IFC510
To ensure the integrity of public safety radio communications, the highest level of filtering is required – both uplink and downlink, especially the case of off-air signal pick-up and delivery. The Dali Matrix® PS uses advanced digital signal processing and agile digital filtering to provide distortion free and intermodulation free radio channels (up to 32). The system provides users selectable downlink and uplink filters with bandwidths ranging from 12.5 kHz to 1.0 MHz. Channelization can be set locally or remotely via the graphical user interface (GUI). With this flexibility, system integrators and public safety operators can deploy systems in selected channels and bandwidths, and then easily reconfigure via software to operate within another set of channels or bandwidths as future requirements change.
The ability to carry optical signals over a long distance, as far as 40 km or further (up to 30 dBo optical link budget) is the result of Dali Matrix PS’ digital signal transport. It enables new deployment scenarios such as centralized headend architecture, and other indoor and underground applications, such as tunnels, subway systems and mines, without adding additional boosters and/or headend units.
The flexibility provided by Dali Matrix® PS is a key aspect to achieving the lowest total cost of ownership. The all-digital architecture enables multiple network topologies including star, chain and hybrid configurations to cater to different deployment scenarios. These network topologies provide reduced fiber plant usage and installation cost, and can also provide effective redundancy configurations.
In addition, with the ability to cascade host units, Matrix PS can support centralized headend architectures and can easily enable new RF sources from different locations to be incrementally added to the existing distribution network without introducing passive intermodulation (PIM).
A transparent 1 Gb/s Ethernet channel on each fiber connection can be used to carry IP traffic from other IP devices such as IP cameras, digital announcement systems, Wi-Fi access points, and others.
Seamless public safety communication is required at all times. The system cannot suffer loss of service due to single of point of failure; therefore, redundancy is very important to ensure that communication between the first responders does not get interrupted.
With its all-digital nature, Dali Matrix® PS can provide a range of redundancy features including redundant hosts, redundant RF modules inside of the hosts, redundant remote units, redundant optical links, and automatic equipment failure detection and switchover.
1:1 redundancy is achieved by deploying a secondary host in parallel operating mode and the same can be accomplished at the remote site by deploying a secondary remote unit with an optical and RF bypass kit. Fiber diversity can be attained by deploying a secondary fiber that runs on a different path from the host to the remote unit.
Another feature that is unique to Matrix PS is the automatic equipment failure detection and switchover. In the case of primary host failure, and/or primary fiber failure, the intelligent remote unit(s) will detect a loss of signal and automatically switch to the secondary optical link and secondary host. In addition, Matrix PS will automatically measure and compensate delays towards the remotes that are caused by the introduction of the secondary optical link. This is important for narrowband waveforms, but will become particularly important with broadband waveforms like LTE which has a stringent delay imbalance requirement.
Dali’s all-digital and software-configurable platform supports Firstnet and LTE waveforms today, hence integrators and public safety operators can easily transition from P25 Phase I and II or TETRA/Tetrapol to LTE. This platform is also future ready since new waveforms/standards can be easily implemented. This is possible since the digital signal processing is conducted using Field Programmable Gate Array (FPGA) devices that enable changes or upgrades by simply uploading a new image into the FPGA. Therefore, with an all-digital and software configurable solution, integrators and public safety operators only need to make the hardware investment initially, and can simply expand and upgrade their network without a major overhaul.
Traditionally, optical delay compensation is done by using the same length of fiber to all remotes, or manually calculating the delay and adding delay elements to synchronize transmission from the antennas. With an all-digital and software-configurable platform, the optical delay is measured and the compensation is calculated. Then the delay is normalized automatically across all fibers with just a click of a button to synchronize transmission from multiple simulcast antennas. This saves site engineers’ time as no additional hardware is required to fine tune delay once the public safety system is installed.
Secure radio communications between first responders and public safety organizations is required. The system should apply features counteracting eavesdropping, content tempering and content forging. Besides the encryption done by the LMRs or trunked radio systems, Dali Matrix PS adds additional scrambling of the data being transmitted over the fiber link, further increasing the protection of the content if intercepted during transport.
In addition, access to the control and management (C&M) functions is password protected and encrypted. This is achieved using HTTP Secure protocol (HTTPS), or HTTP over secure socket layer (SSL), or with transport layer security (TSL) that provides authentication and bi-directional encryption of communications across the Matrix PS network.
With the flexible and scalable nature of Dali Matrix PS, integrators and public safety operators can choose rather to have cellular and public safety in-building coverage as a separate system or an integrated system. Both options are available with an all-digital solution and the decision is based on each project’s goals, requirements and design. With up to 320 MHz of aggregated bandwidth per wavelength, Dali digital platform can support both cellular and public safety frequency bands over the same fiber.
The hdHost™ PS is a quad-band host unit supporting up to 4 bands designed to interface directly to the Base Station (BTS) or other RF sources such as the bi-directional amplifier (BDA).
On the downlink (DL) path, the hdHost PS receives RF signals from the RF sources and then converts these RF signals into a digital data stream. Third party IP data can also be added, and the aggregated digital data stream is then delivered via fiber optic links at a data rate of 10 Gb/s to the remote radio units.
On the uplink (UL) path, the hdHost PS performs the reverse functions and delivers the RF signals back to the corresponding base stations , and the IP data to the internet network.
The airHost33™ PS is a dual/quad-band host unit designed for off-air interfacing to public safety base stations with the airHost33 accepting analog RF signals from off-air donor antenna(s). The dual-band unit can process 1 to 2 public safety bands simultaneously and the quad-band, 1 to 4 bands.
On the downlink (DL) path, it translates analog RF content into a digital data stream, and then transports it to remote units over one or more of 8 independent optical links at a data rate of 10Gbps. The airHost33 also supports 1Gbps Ethernet backhaul for additional IP devices such as security cameras and Wi-Fi access points that located close to the remote units.
On the uplink (UL) path the airHost33 receives data streams of digitized RF signals from the remotes, which it then get converts back to analog RF. The RF signals are filtered and amplified to a composite power of up to 2W per band. The signals are delivered back to a macro radio tower via an outdoor directional antenna.
The hd37™ PS is a dual-band medium-power remote unit with 5 W or +37dBm of output power per band. hd37 PS bi-directionally transfers two bands respectively over a single optical fiber (Single Mode Fiber) at 10 Gb/s with optical link budgets from 15dBo to 30dBo. It also accommodates 1 Gb/s Ethernet backhaul.
The hd37 PS utilizes pluggable RF modules (RFM) with an output RF power of
5 W. The hd37 PS can be optionally configured for single or dual-band operation. The hd37-RFM modules are radio access technology agnostic.
The hd37 PS connects to Dali’s hdHost PS or airHost33 PS head-end in a star, daisy-chain, or hybrid star/daisy chain configuration. The hd37 PS can incorporate an optical and RF bypass kit that enables 1:1 remote redundancy. Built in intelligence enables automatic switchover between primary and secondary fiber links when loss of synchronization/data continuity is detected. Monitoring and control of the hd37 PS can be performed locally via the Ethernet craft ports or remotely through the hdHost PS. All units are convection cooled that contribute to high Mean Time Between Failure (MTBF).
hdHost37 PS is a channelized unit where 16 to 32 frequency segments can be filtered using agile bandpass filters with adjustable bandwidth from 12.5
kHz to 1MHz. Both band-selective and channelized versions are available.