Is NEXEDGE® compatible with other companies’ products and systems?
Yes. The NXDN™ protocol used by NEXEDGE® is compatible with other companies’ products that conform to the mandatory features and standard optional features specified by the NXDN™ Forum. Details are provided on the Forum website.
Is NEXEDGE® compatible with P25?
Not directly, since the NEXEDGE® radio system uses the NXDN™ protocol, whereas P25 radio systems use the TIA-102 standard. Since these systems use different protocols they cannot communicate with each other. However, KENWOOD Solution Developers Program (KSDP) partners and other solution providers are currently developing gateways to enable two-way connectivity between different protocols. Note that Kenwood has its own range of P25-compatible radio equipment.
Is NEXEDGE® compatible with TETRA?
No. TETRA is a 4-slot TDMA radio system, standardized by ETSI. However, KENWOOD Solution Developers Program (KSDP) partners and other solution providers are currently developing gateways to enable two-way connectivity between different protocols.
Is NEXEDGE® compatible with DMR?
No. DMR is a 2-slot TDMA radio system. However, KENWOOD Solution Developers Program (KSDP) partners and other solution providers are currently developing gateways to enable two-way connectivity between different protocols.
Is NEXEDGE® compatible with dPMR?
Some NEXEDGE® radios can be made dPMR compatible by rewriting the radio firmware using programming software, but the CAIs are incompatible.
We currently use an FM analog system. Can we gradually migrate to a NEXEDGE® digital system?
Yes. NEXEDGE® is flexible enough to make it possible to migrate from FM analog to NEXEDGE® digital at your own pace.
As regards NEXEDGE® making effective use of current FM analog systems, specifically what components are of use?
You can use power amps, combiners and other equipment that form part of FM analog systems. Moreover, NEXEDGE® radios have a digital mode and an FM analog mode, so it is possible to gradually convert systems currently in use from FM analog to digital. Also, absolutely no special peripheral equipment is required for 6.25 kHz operation; standard LMR facilities can be used as they are.
Does mixed mode work only in conventional mode?
Yes. Mixed mode is available only for “conventional” operation (FM analog conventional & NEXEDGE® conventional).
To whom do you recommend NEXEDGE?
We recommend NEXEDGE® to users with the following needs/issues:
- “Our present equipment suffers from a kind of rasping noise on the edges of the communications area.”
- “We want to extend the range a little, but we are hesitating because of the cost of installing repeaters.”
- “With our present equipment, competitors can eavesdrop on our communications and important information is being leaked. We know we could prevent this with scramblers, but they are expensive.”
- “We want to send GPS positional information with voice simultaneously, and sometimes we want to send long data messages instead of voice, but right now we have neither of these capabilities.”
- “We currently use LTR trunking, but we only have about 200 IDs, which is inconvenient.”
- “We are operating a multisite system, but running costs are high because we have to use leased lines to connect the different sites.”
- “We are running a system as an SMR operator, but too much time is spent in managing IDs and accounting. We want something simpler.”
- “We want to make the right choices now so that we will not be faced with additional costs if and when we are compelled to transition to 6.25 kHz.”
How is it that both FM analog and NEXEDGE® units can share the same RF channel?
With conventional operations using 12.5 kHz channels, NEXEDGE® radios can be used in either FM analog or digital mode. However, since the frequency is the same, a choice must be made between FM analog and digital. For example, if someone transmits in FM analog mode, the receiving unit will switch automatically to FM analog. Similarly, for digital mode transmissions the receiving unit will switch to digital and decode the digital voice signal.
How is it that both voice and data be transmitted simultaneously on the same channel?
With FM analog communications, it is not possible to transmit voice and data simultaneously, but this can be done using digital mode. This is because digital technology converts the voice signal into a digital signal for transmission; in other words, both voice and data are transmitted together as a digital signal. At the receiving end, the voice and data are separated and individually decoded.
How far exactly does NEXEDGE® coverage extend?
It is not possible to precisely compare coverage areas since they vary depending on the conditions for radio wave propagation. However, when comparing coverage areas under the sort of conditions typically encountered, NEXEDGE/NXDN™ technology offers better audio quality at the extreme fringes of radio coverage. In addition, using narrower 6.25 kHz channels means that receiver filters are narrower too and so RF sensitivity can be increased.
- Comparing digital 6.25 kHz operation with digital (TDMA or FDMA) 12.5 kHz operation, the former offers 15% longer range, which works out as 30% greater coverage area.
- Comparing digital 6.25 kHz operation with FM analog 12.5 kHz operation, the former offers 20% longer range, which works out as 50% greater coverage area.
How will we conduct on-site measurements when operating 6.25 kHz digital communications? Do we need special testing equipment?
No special testing equipment is required: tests can be conducted in standard 12.5 kHz channel spacing. However, the frequency stability of the KXK-3 OCXO unit is +/-0.15 ppm, with a 2-year aging characteristic of +/-0.25 ppm. To ensure that any deviation is within the 0.5 ppm specified for UHF, maintenance is needed every two years. Also, a high-precision reference oscillator and frequency counter capable of measuring from 10 to 1 Hz are needed for adjustment of the OCXO.
Do we have to use a high-stability clock for 6.25 kHz operation?
FCC Part 90 specifies that frequency stability must be within +/-0.5ppm for a UHF base station operating with a 6.25 kHz-wide channels. If your country/region mandates this for 6.25 kHz operation, please use the optional KXK-3 high-precision OCXO. However, if your system works on 12.5 kHz channel bandwidth, the KXK-3 is not required even in 6.25 kHz very narrow mode.
For 6.25 kHz trunked operation, the optional KXK-3 must be used whatever minimum frequency stability is mandated (VHF/UHF).
Is it possible to make a backup file of the entire system (containing all hardware and user data)?
Yes, but a complete system backup comprises 2 files: a KPG-110SM data file containing the system configuration, and a KPG-109D data file containing the frequency configuration.*
- KPG-110SM is the NEXEDGE® Trunking/IP System Manager for Windows; KPG-109D is Windows programming software.
Is it possible to mix KENWOOD NEXEDGE® radios used in peer-to-peer direct mode with IDAS transceivers manufactured by ICOM?
Yes. Basic interoperability has been confirmed, although some data CAIs are not compatible since they have been developed independently.
Can we connect multiple repeaters using the IP network?
Yes, KENWOOD NEXEDGE® system repeaters can be connected via IP.
When running a trunked radio system, can we remotely monitor operating performance and statistics? Some kind of dial-in facility would be great.
Yes, KENWOOD NEXEDGE® KPG-110SM System Manager software offers these features. Also, server-based NEXEDGE® 2nd Generation offers multi-point remote monitoring using the Network Manager’s asset monitor software.
When sharing NXDN™ digital voice channels with FM analog voice channels, can we keep on using CTCSS tones in the FM analog channels?
Software is available to configure the shared channel as either “shared” or” AUX”. Both operating modes employ CTCSS signaling for a radio’s built-in decoder/encoder, if required.
What are the advantages of NEXEDGE® 2nd Generation?
If building a multi-site trunked system with NXDN™ Type-C trunking, the maximum number of sites is limited to 48. NEXEDGE® 2nd Gen, however, is effectively limitless, being capable of linking up to 1,000 sites. Moreover, the adoption of an advanced server-based system design has taken virtually all aspects of operation to the next level, with expanded system monitoring (SNMP) and configuration capabilities, as well as remote functions and reduced downtime when reconfiguring the network. Also, a zero-based software review has resulted in a significant increase in GPS data communications capacity.
Is NEXEDGE® 2nd Generation fully compatible with the 1st Generation?
Basic 2nd Gen functions are compatible with 1st Gen, and NXR-x00 Series repeaters need only have their firmware updated. 2nd Gen is also compatible with the existing NX IP interface, and equipment developed for 1st Gen can be used with 2nd Gen. However, since 2nd Gen involves building an advanced server-based system, it does require new hardware and software.
Is NXDN™ an open standard?
NXDN™ is an open standard supported by multiple leading vendors in the professional communications industry; the NXDN™ Forum currently has over 30 members. The standards suite was widely opened to the public domain, and there is a legitimate interoperability qualification system.
Is NXDN™ a proven technology?
Yes. We have invested many years and significant resources in the development of NXDN. NXDN™ specifications were first verified using computer simulations, and then checked in countless field tests using NEXEDGE® prototypes prior to launch. Since then, over a million NEXEDGE® subscriber units have been shipped, leading the way in the global adoption of NXDN™ and winning acclaim worldwide.
Why did KENWOOD develop NXDN?
When a public body decides on standard technical specifications, as is the case with APCO and TETRA, compatible equipment from different manufacturers can be used together. However, in the case of digital radios for business applications, the process of deciding on standard technical specifications was held up, meaning that equipment from different manufacturers would not be compatible. Nevertheless, it was necessary to prepare for the anticipated FCC requirement for Part 90 licensees to migrate to 6.25 kHz narrowband technology. So that business users would not be at a disadvantage, we engaged in joint research and developed a standard protocol for digital communications.
What are the most significant benefits of using the NXDN™ protocol?
The following are especially noteworthy:
NXDN™ offers clear digital voice communications with little or no noise. Thanks to digital modulation, a high degree of confidentiality is available. Current FM analog equipment (power amps, combiners, etc.) can continue to be used. Since voice and data can be transmitted at the same time, it is easy to add data to radio communications even without a reserved frequency. You can also be sure of coverage that is significantly better than that of an FM analog system. This means that, in a multisite system, you can achieve the same area coverage with fewer sites.
Is NXDN™ (digital) robust when it comes to interference?
Switching to digital does not mean that one can solve the RF-based interference suffered by today’s systems. Adjacent and co-channel interference will sound different when using digital equipment, but digital technology in itself will not solve historic interference issues. Nevertheless, the 6.25 kHz very narrow bandwidth operation of NXDN™ is essentially less prone to adjacent interference than FM analog 25 kHz or 12.5 kHz bandwidth operation, since it allows for space in the spectrum that effectively serves as a guard band.
Is it possible to scan NXDN™ trunking zones and conventional zones?
If an NXDN™ trunking zone is selected and a scan is initiated, the scan is available for only that zone. Similarly, if a conventional zone is selected for a scan, the scan is available only for conventional zones. This means that is impossible to scan NXDN™ trunking zones and conventional zones together.
What sort of systems use FDMA?
The FDMA access method has been employed in many LMR trunked systems such as LTR, SmartNet, and MPT 1327. P25 Phase I for digital public safety radios also uses an FDMA access method.
What are the benefits of FDMA?
In order to satisfy the spectrum efficiency requirement for one voice path per 6.25 kHz bandwidth, one can employ the 2-slot TDMA (12.5 kHz channel) method, but FDMA is superior for large zones and for direct communications between radios. FDMA is also simpler than TDMA when it comes to servicing and maintenance. Basically with the 2-slot TDMA method, in direct mode operations only one of the slots can be used for communications, so 6.25 kHz frequency efficiency is not achieved (it requires complex control). With TDMA the guard time required between slots to prevent data collision reduces the coverage area and the effective data rate per slot; FDMA is not subject to such limitations.
What is an OCXO and when do I need to use it?
The radio laws in each country specify the minimum acceptable transmission frequency stability. For example, for UHF transmissions the FCC in the United States and Canada’s IC require a frequency stability of ±0.5ppm for a base station operating with 6.25 kHz-wide channels. An OCXO oscillator unit is necessary to ensure this high level of frequency stability.