Digital Radio Rebanding
Digital Radio Rebanding
In this paper we have talked about the urgent need of introducing more Emergency communication RF frequencies. The reason for needing more frequencies are twofold firstly the frequencies already allocated are much less than needed and secondly all these frequencies needed upgrade the . We have also included frequencies currently used for emergency networks. We have talked about a scenario where the equipment upgrade became necessary when the emergency support system was changed to a different frequency. Later in the paper we have recommended using new digital technologies such as software defined radio, cognitive radio and 802.
11 Adhoc networks for stronger , secure, high data rate and reliable communication. Introduction As the world is moving ahead the need for radio and wireless communication cannot be denied. This importance becomes more evident in emergency conditions and times . Several frequencies from the electromagnetic spectrum are allocated for emergency time communication by the governments and agencies around the world. One such agency is FCC who is responsible for assigning different frequency bands/ There are some specific frequencies that are the designated for the communication in emergency, a table of such allocated frequencies are presented here.
The problem is this that these frequencies are being used for other purposes by the hobbyist etc for communication or other type of data transfer at other times and accessing these in the time of emergencies becomes difficult. The aircraft emergency frequency is a set of frequencies used on the aircraft radio band reserved for emergency communications for aircraft in distress. The frequencies are 121. 5 MHz for civilian, also known as International Air Distress (IAD) and 243. 0 MHz for military use, also known as Military Air Distress (MAD).
Both of these frequenices are used on the international level. Digital Radio Rebanding It is a well know fact that Electromagnetic spectrum is a limited source hence the whole electromagnetic spectra has been dived to be used for specific purposes, one of such specific purpose is to use Radio frequency based communication in time of emergency. Several specific bands are allocate for this purpose but it has recently been felt that these bands do not provide the required frequencies and modern digital radio will also not be able to perform well in these bands. (Silva, 2001).
Since these frequencies are limited these also become crowded at those times of emergency when a lot of people are communicating for rescue and providing help. i. e in the case of a major disaster several aid agencies and organizations approach that place, they use similar equipment and find themselves unable to communicate. Therefore it is a dire need to increase the number of these allocated frequencies only designated to be used for emergency purposes. At several times in the past the required emergency band were found to be occupied and the users were asked to quit using those frequencies o n that period.
One of the outstanding examples is of NOAA satellites which has got its frequencies changed in February 2009 and now it can only receive signals from the 406 MHz frequency beacons. It should be noted that NOAA satellite was crucial in saving at least 283 people worldwide. The older emergency beacons, operating on the 121. 5 and 243 MHz frequencies, will no longer be detected. This is one of the main ressons why all the equipment on the ground that they use needs to be upgraded. Events where the emergency systems failed In the recent history during several disaster the need for ditial radio rebranding has been felt.
The three major events have high importance in this regard. During Hurricane Katrina, the emergency frequencies were found to be inadequate and were not able to cope up with the requirements. The emergency spectrum was very crowded and more people were found trying to access the channel than the spectrum could possibly accommodate. Emergency communication systems failed on the disastrous event of 9/11 and caused the people working in those agencies to evaluate their system performance. The Indian Ocean Tsunami that occurred in 2004 and caused approximately 350,000 deaths and many more injuries.
There could be much less deaths if the emergency communication could be on digital equipment and more spectrums dedicated. Digital Radio Analog systems, which are predominantly existent in today’s emergency communication, are cheaper but digital systems present much more efficient, better performance, and greater flexibility. For the public security radio communication has been used as a primary means of communication for several organizations including police but there are slight improvement in the methods used to transfer information.
This lack of innovation over time has lead to the overcrowding of current systems and the need to find new and better methods to communicate in that medium. Recent tragic disaster raised concerns about the existing public safety emergency communications and their inability to accommodate a large number of users for a short time is serious problematic. These currently systems failed to offer the kind of rescue help as it was thought earlier. With the implementation of digital technology the allocated frequency band would allow for the increased use of the spectrum.
Current frequencies and added new frequencies that would better allow many agencies to communicate with limited problems when compared to current operational models. Unfortunately more focus is there on improving day to day communication because they yield more business but serious concerns are there and which need to be addressed as several analog based systems failed to be effective in emergency communication. Recommendations By analyzing the situation we can easily say that the reserved frequencies used for emergency communication are much less than what are needed.
Hence more frequencies are needed for emergency communication bands, FCC and other frequency allocated organizations need to ponder greatly on this aspect. Also it should also be made sure that nobody except the authorized users use those frequencies hence in the case of any emergency, the communication could be established in no time. We have also found that the analog radio communication is inefficient therefore radio digital broadcasting is necessary in the times of emergency and agencies already working such
It is also imperative for the agencies involved in emergency operation to have all their equipment based on digital radio. It is one in which all the communications is done using digital modulation techniques: here we would talk about some of the recent advancement in digital radio technology which has increased the reuse of frequcnices with better transfer of data, voice and video both. Software defined Radio is one of the very promising technologies and will prove to be one of the major developments in the field of RF communication.
If SDR , as it is called , is introduced in emergency communication equipment data communications, voice communications, video communications, would all be made possible in much better ways for the emergency response communications. ( Kenington, 2005) SDR is usually a collection of hardware and software technologies in which a few of the radio’s operating functions such as physical layer processing are implemented through reconfigurable software which is burned into the different programmable processors.
The SDR has now been seen to be implemented using field programmable gate arrays (FPGA), digital signal processors (DSP), general purpose processors (GPP), embedded systems or other specific programmable processors. With software defined radio new technologies can easily be built to existing radio systems without requiring new hardware. (Reed, 2002) In reality the Software defined radio (SDR) technology brings flexibility and cost efficiency and will be very helpful in the long run for the emergency radio rebranding takes place as no matter what frequencies are assigned; only tweaking the software would enable the communications.
Cognitive radio technology Cognitive radio can be implemented specially for the emergency needed communication because this promising technology would accommodate many more users than the usual analog or digital communication methods. (Arslan, 2007) Recent studies demonstrated that dynamic spectrum access can improve spectrum utilization significantly by allowing secondary unlicensed users to dynamically share the spectrum that is not used by the primary licensed user. Cognitive radio was proposed to promote the spectrum utilization by opportunistic exploiting the existences of spectrum holes.
( Fette, 2009) Other Technologies Few recent technologies such as WiMAX (802. 16) might be deployed in conjunction with traditional communication modes to enhance the data rate so that images from the disastrous area might be transferred to remote areas. One other technology that is taking shape these days is 802. 11 adhoc sensor networks which might also be deployed in remote areas so that if any one needs rescue they could be helped. The adhoc networks are recently introduced technology and might prove to be very useful.
Today the rescue teams are capable to do much more for the people in need and in emergency conditions based on the information they have but for this they need detailed information in the form of pictures videos and detailed maps, The legacy analog radio systems are unable to support high data rates nor are cable of handling simultaneously. Conclusion: We conclude from this study that not only the frequencies assigned are less than the required, considering the events where these frequencies were exhausted and also the equipment in use is also needs to be based on Digital Radio.
If the new frequencies are acquired it has also been found out that the equipment becomes useless so both of these needs to be achieved for a better RF emergency communications. References Silva, E. D. (2001), High Frequency and Microwave Engineering . Newnes Kenington, P. (2005) Rf And Baseband Techniques for Software Defined Radio. Artech House Publishers Arslan,H. (2007) Cognitive Radio, Software Defined Radio, and Adaptive Wireless Systems . Springer Fette,B. A. (2009)Cognitive Radio Technology, Second Edition. Academic Press Reed, J. H. (2002) Software Radio: A Modern Approach to Radio Engineering. Prentice Hall PTR