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DMR Tier III: the open standard for radio communications

Posted

Some of the professional writers on the internet are at a really high level that i ponder if any of them have ever written a book? so from time to time i like to focus on these first-rate articles and here's one i found interesting the other day.

Private mobile radio is fast becoming an essential communications solution to support the operational needs of utilities companies, airports, oil and gas pipelines and emergency services.

When compared to public cellular services, it delivers improved coverage, reliability and resistance, contention, security, group communications and performance.

The digital landscape is crowded, though, with a number of public safety digital standards such as TETRA, P25 as well as low cost digital solutions including DMR (Digital Mobile Radio), dPMR (digital Private Mobile Radio), NXDN and PDT (Professional Digital Trunking).

DMR is coming out on top thanks to theopen standard nature of DMR Tier III trunking, which is driving its emergence, ongoing development and adoption across global markets.

But do open standards matter? While open standards are less important in the small system market, they are critical to the long-term case for the radio system in the medium to large systems sector, and it is here that open standard DMR Tier III will dominate.

Essentially, DMR Tier III trunking features a control channel on each radio site and allocates traffic channels on demand making it frequency efficient and enabling a large number of users to share a relatively small number of channels. Radio sites can easily be inter-connected, usually using IP connections, making it possible to deploy systems ranging from a single site to hundreds of sites spread over a large geographical area.

The open standard way

The DMR standard includes the facility for implementers to provide 'manufacturer extensions', enabling manufacturers to provide proprietary features within the framework of the DMR air interface definition. This allows them to complement the standard set of DMR call functions with their specific facilities.

This has the advantage of enabling customers to request specific functionalities to support the manufacturer's business operation needs and also enables them to provide innovative features that differentiate their solutions from others implementing the same standard.

One disadvantage to this offering is that interoperability can only be possible for those features that are fully defined by the standard and that customers using manufacturer extensions are effectively locked in to a single manufacturer solution rather than enjoying the vendor choice that a standard enables.

To address the pros and cons, the DMR Association (DMRA) has struck a balance between robustness and cost with their interoperability process, which focuses on testing the conformance of products against the published standard that describes the over-air signalling. The DMRA facilitates testing between a terminal manufacturer and an infrastructure manufacturer, and the two parties carry out the testing against a standard test specification. Test results and logs of all messages sent over air are recorded during the testing and then are inspected by one or more independent third parties during a detailed review meeting. Only after the independent third parties are satisfied that the equipment under test has conformed to the open standard specification is an interoperability certificate issued.

Ongoing standards development

Whilst this facility can be useful, extensive use of manufacturer extensions would call into question whether DMR was a standard that delivers interoperability (and therefore vendor choice) or whether it results in proprietary solutions rather than following an open standard.

The answer to this lies in the work of the DMR Association. The DMRA has a technical working group - made up of competing manufacturers - who collaborate to ensure the standard succeeds. Any proprietary features from the manufacturers, which are believed to have wide market appeal or have useful features the standard doesn't yet specify, are debated in the group. They are then developed to further advance the standard to the benefit all of the manufacturers and indeed the customers who choose to implement DMR technology.

The DMRA is further developing the standard to meet future market demands by identifying important new features and ensuring these are developed and included in new releases of the ETSI standards.

The future of DMR Tier III

Open standards are critical to providing long-term support and stability to customers. The adoption of the standard by a critical mass ensures its longevity over other similar competing technologies that have lower levels of support by offering the market vendor choice and maintaining low costs.

Is DMR Tier III radio communications' open standard for the future? Yes. Due to DMRA's authority, the robust and well-supported interoperability programme and the long-term commitment of a large number of manufacturers, it is emerging as the most successful low cost digital technology for complex projects - and therefore the open standard that no other private mobile radios can contend with.

Source - http://www.telecomstechnews.co m/news/2014/apr/25/dmr-tier-ii i-open-standard-radio-communic ations/

WW1-Era Shipwrecks To Receive Protection

Posted

July 28th 1914 was a day that changed the world forever.

A global war was declared that would last for four long, bloody years and would cost Humanity millions of lives. Although the images of the gruelling, inhuman trench warfare that was waged in France are the perhaps most indelible from the conflict, it should also be remembered that an awful amount of lives were also lost at sea.

Britain alone lost over a thousand vessels from 1914 - 1919, together with about 89,300 sailors and merchant navy personnel. Germany lost hundreds of warships, as well as about 35,000 sailors. In addition, civilians were also caught in the ocean-going crossfire, as a German submarine sank the liner Lusitania in 1915, killing almost 2000 people in the process.

As we approach the centenary of the First World War, the seafloors are littered with the stark, skeletal remains of vessels leftover from this conflict. In recent years, however, these ruined ships have come under an increased level of threat from salvage teams, looters and profiteers, many of whom are intent on destroying the wrecks outright.



Shipwrecks such as those left over from the First World War, are a target for two main reasons. Firstly, they can be commercially exploited for scrap metals (and other artefacts) and secondly, fishing trawlers dredging the ocean depths in search of deep-sea fish can impact the ships, destroying them altogether.

In 2011 alone, three British cruisers, the final resting place of about 1,500 sailors altogether, were completely destroyed because copper and bronze had reached sufficiently high prices as to make such destructive salvage exercises profitable.

However, because the 100th anniversary of World War One begins this year, more and more of these ships will be protected by Unesco's 2001 'Convention on the Protection of Underwater Cultural Heritage', an agreement that extends International protection toshipwrecks over 100 years old.

Many people worry that these laws will prove difficult to enforce, however. Others still are worried that this move will increase the destruction of shipwrecks from more recent times, in particular, vessels from World War Two (1939 - 1945), before they come under Unesco's protection.

Today, historians are attempting to use the centenary of the First World War as a way to educate people about the history and legacy of the conflict, as well as to demonstrate the cultural and historical importance of these undersea war graves. Many, including this writer, feel that such sites are deserving of our respect and reverence.

Shipwrecks also provide a very good habitat for local marine life and can even form the basis for coral reefs (if left undisturbed for long enough). These vessels are also studied for scientific interest, with experiments carried out on everything from metal erosion to marine biology.

At the time of writing, the British Government has failed to sign the convention.

SOURCES

http://www.bbc.co.uk/news/scie nce-environment-28056244

WW1-Era Shipwrecks To Receive Protection

Posted

July 28th 1914 was a day that changed the world forever.

A global war was declared that would last for four long, bloody years and would cost Humanity millions of lives. Although the images of the gruelling, inhuman trench warfare that was waged in France are the perhaps most indelible from the conflict, it should also be remembered that an awful amount of lives were also lost at sea.

Britain alone lost over a thousand vessels from 1914 - 1919, together with about 89,300 sailors and merchant navy personnel. Germany lost hundreds of warships, as well as about 35,000 sailors. In addition, civilians were also caught in the ocean-going crossfire, as a German submarine sank the liner Lusitania in 1915, killing almost 2000 people in the process.

As we approach the centenary of the First World War, the seafloors are littered with the stark, skeletal remains of vessels leftover from this conflict. In recent years, however, these ruined ships have come under an increased level of threat from salvage teams, looters and profiteers, many of whom are intent on destroying the wrecks outright.



Shipwrecks such as those left over from the First World War, are a target for two main reasons. Firstly, they can be commercially exploited for scrap metals (and other artefacts) and secondly, fishing trawlers dredging the ocean depths in search of deep-sea fish can impact the ships, destroying them altogether.

In 2011 alone, three British cruisers, the final resting place of about 1,500 sailors altogether, were completely destroyed because copper and bronze had reached sufficiently high prices as to make such destructive salvage exercises profitable.

However, because the 100th anniversary of World War One begins this year, more and more of these ships will be protected by Unesco's 2001 'Convention on the Protection of Underwater Cultural Heritage', an agreement that extends International protection toshipwrecks over 100 years old.

Many people worry that these laws will prove difficult to enforce, however. Others still are worried that this move will increase the destruction of shipwrecks from more recent times, in particular, vessels from World War Two (1939 - 1945), before they come under Unesco's protection.

Today, historians are attempting to use the centenary of the First World War as a way to educate people about the history and legacy of the conflict, as well as to demonstrate the cultural and historical importance of these undersea war graves. Many, including this writer, feel that such sites are deserving of our respect and reverence.

Shipwrecks also provide a very good habitat for local marine life and can even form the basis for coral reefs (if left undisturbed for long enough). These vessels are also studied for scientific interest, with experiments carried out on everything from metal erosion to marine biology.

At the time of writing, the British Government has failed to sign the convention.

SOURCES

http://www.bbc.co.uk/news/scie nce-environment-28056244

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michael1996
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