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Licensed Spectrum sharing, Unlicensed Spectrum 
sharing and Secondary Spectrum Access 
Rafi Ullah Khan, Naeem Aslam, Motsa...
Licensed spectrum examples are use of the harmonized ECS 
bands (790-862 MHz, 880-915 MHz, 925-960 MHz, 1710- 
1785 MHz, 1...
and into smaller slices, these slices are basically called 
sectors, if we add these sectors the it will complete a cell. ...
locations and at the very long distances from the source 
channel. 
The TV receiver which can be very effected to 
adjacen...
walls. The common channel interference is located at the roof-top 
so it will exhibit low interference as compared to the ...
Conference on Cognitive Radio Oriented Wireless Networks 
Communications (CROWNCOM), Jun. 2010. 
[13] H. Karimi, “Geolocat...
Conference on Cognitive Radio Oriented Wireless Networks 
Communications (CROWNCOM), Jun. 2010. 
[13] H. Karimi, “Geolocat...
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Licensed Spectrum sharing, Unlicensed Spectrum sharing and Secondary Spectrum Access

Licensed Spectrum sharing, Unlicensed Spectrum sharing and Secondary Spectrum Access

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Licensed Spectrum sharing, Unlicensed Spectrum sharing and Secondary Spectrum Access

  1. 1. Licensed Spectrum sharing, Unlicensed Spectrum sharing and Secondary Spectrum Access Rafi Ullah Khan, Naeem Aslam, Motsaim Sohail The department of Telecommunication Engineering The Islamia University of Bahawalpur (BWP) Bahawalpur , Pakistan Engr.rafi18@gmail.com Naeemaslam14@gmail.com Somig7@gmail.com Abstract—now a day there is lots of work is happening on the sharing of spectrum. First of all we have to know about that what is spectrum sharing and how we can share spectrum. Sharing of spectrum is the most critical part of the telecommunication society and if we or someone else want to use licensed spectrum sharing then we have to pay for it. In licensed spectrum sharing there is some bands that are defined by the international telecommunication union (ITU). The next type of spectrum sharing is the unlicensed spectrum sharing in which is unlicensed spectrum of frequency is used and whoever want can use that portion of frequency. The use of unlicensed spectrum is free of cost and there is no rules and regulation for the unlicensed spectrum. The ratio of VHF/UHF wideband is used for the secondary spectrum access candidate, which is also named as TV white spaces. Keywords—Licensed spectrum sharing, Unlicensed spectrum sharing, FCC (federal communication commission), Sectoring, HAN (home area network), Neighbour area network (NAN), Distribution area network (DAN), Very high frequencies (VHF), Ultra High Frequency (UHF) 1 LICENSED SPECTRUM For more than 20 years broadband mobile networks are developed using licensed or dedicated spectrum. Commercially all cellular networks are assigned spectrum bands to operators in dedicated blocks. These dedicated frequency bandwidths are often assigned by competitive auctions. Devices operation in the licensed spectrum operates in the portion of that radio spectrum which is designed by FCC. That spectrum is for those organizations which have bought or which are granted by the licenses ot radio spectrum. Having the rights of license, a radio spectrum user operates without interference of radio channels or frequencies and also without crowding in the radio spectrum. Law enforcement and legal protection is provided by FCC when other operators transmit over the similar frequency and within the similar geographical area. FCC prevents them from using someone else’s spectrum. An organization has legal rights to use the frequencies allotted to that organization with in the same area after purchasing the license. Communications in these bands have power limitations and also use carrier of single frequency so in fact the tendency of these communications is purely narrow band by nature wise. Due to excellent ratio of signal and noise (S/N), licensed spectrum have clear advantages over undedicated frequency or unlicensed frequency spectrum. Potentially, strong level of signals is almost 10 to 100 times more powerful than undedicated spectrum of frequencies when central collector is use in the system. Instead, having multiple of miles between end users, wireless network can transmit up to 20 miles between them easily. Licensed spectrum although have multiple advantages over unlicensed spectrum, it is scarce resource which is difficult to manage and expensive to adopt. Limited availability of frequency bandwidth can be an issue to deal with. The only FCC licensed communication network is Senses Flex Net system which is designed particularly for utilities of water, electric and gas. This system acquired protected spectrum to solve the issues of water, gas and electric and aids their customers to overcome the issues which their customers faces. These issues are overcome by using 325 kHz bandwidth along with the highest RF powers. A worldwide example of licensed spectrum is shown in the following figure1.
  2. 2. Licensed spectrum examples are use of the harmonized ECS bands (790-862 MHz, 880-915 MHz, 925-960 MHz, 1710- 1785 MHz, 1805-1880 MHz, 1920-1980 MHz, 2110-2170 MHz, 2500-2690 MHz, and 3400-3800 MHz) which are used for the provision of electronic communication services. In such cases, responsibility to protecting the licensed user against interference is taken by the regulator and it also provides a legal basis for ensuring a certain quality of service (QoS). Another example of spectrum allocation or licensed spectrum for Ip based networks such as Home Area Network (HAN), Neighborhood Area Network (NAN) and Distribution Area Network (DAN) is given in the following table. 2 UNLICENSED SPECTRUM Unlicensed spectrum bands are those frequency bands that have technical specified rules for both hardware and software, but the number of users are not specifies, it has limitless users. Any user which have certified equipment from federal communication commission (FCC), he can use unlicensed spectrum bands at any time either it is publically purpose or private purposes. There is one expectable usage for the user is that he needs no protection against the interference like in the licensed spectrum bands. The rule that is specified from the federal communication commission for the Wi-Fi purposes are called 802.11 protocols so they can minimize the error of interference. The history of unlicensed spectrum the law which is obeyed by the users is PART 15. After that the national telecommunication and information administration (NTIA) participate for the limitations of unlicensed spectrum frequency bands. The recent technologies are spread spectrum, Wi-Fi, software-defined-radio (SDR), ultra-wideband etc. The bands that are unlicensed significantly are given below and they are specified by the federal communication commission:  3.6 GHz (3650-3700 MHz)  61 GHz (57-64 GHz)  1920-1930 MHz  902-928 MHz  2.4 GHz The question which is raised in all the readers minds that why we need unlicensed spectrum bands?? The answer for that question is to save the licensed bands and other services that may cause to do damage to the licensed spectrum bands and also to protect higher frequency bands. The quality of service in between the licensed and the unlicensed spectrum bands are that, how much facilitate the users and easy access of the spectrum is. In comparison with the licensed, unlicensed spectrum provides better services, technology and devices. For better services we need to build a strong infrastructure and high beam antennas that really increase both of the received and the transmitted power and in this way we can minimize the interference. In the case of licensed share spectrum it will be much more complex to handle and to solve the problems, and the cost of licensed spectrum is very much high [2][3]. 2.1 CHARACTERISTCS  The time required will be less  The bandwidth needs  The required frequency limit for the service 2.2 WHY WE NEED SPECTRUM SHARING The wireless communication is becoming the key part of any type of communication, because it is cheaper, easy to maintain. In every department of our life the communication is backbone for it. The wireless communication providing us capacity and mobile broadband. We used the concept of “SECTORING” in wireless communication. In the sectoring we divide the whole cell with an angle of 360 degree around
  3. 3. and into smaller slices, these slices are basically called sectors, if we add these sectors the it will complete a cell. In fixed sector, the wireless facilities can be provide remotely, but in the case of mobile sectoring the cells are become small due to increasing the cell capacity. The used wireless cellular networks are increasing day by dy, so the scientists should have to develop a method that to increase data rates and number of users in a fives sectors with respect to the recommendation of international telecommunication union, this can be achieved by two ways.  Shrinking of cell  Using more spectrum Fig 2 A Cell Sectoring. 2.3 SHARING OF UNLICENSED SPECTRUM The major problem of unlicensed spectrum is that there are multiple interfaces and the systems on a same place, due to these problems the situation will be arise which will be inefficient for the whole enterprise. To remove the problems of inefficient sharing in the unlicensed spectrum we have to build the enforcing protocols that really suit the situation. The first step is that first of all we will do the all possible responses. We have to make scenario where there are multiple systems are exist at the same place, in the urban dense areas the protocols which e used for the wi-fi purposes is 802.11 networks, and the sharing of spectrum is exist like ISM unlicensed spectrum sharing. In the unlicensed spectrum sharing us build a law that has only one goal is to increase the spectrum efficiency. To increase system efficiency, data rates, and the bandwidth which is compatible for the single system? a resource-allocation is the self-enforcing method without minimizing the system performance. We can used the power transmit limit, this will minimized the amount of interference. For efficient resource allocation we make some situations according to the scenario. The use unlicensed spectrum is depends upon some technical condition, like we discuss earlier that by transmitting low power that will help to minimize the amount of interference. Unlicensed spectrum sharing will be much more efficient, reliable for only low traffic situations if the traffic is high then the contention can arise, for that reason we use carrier sense multiple access. No access codes are implemented in the unlicensed spectrum sharing, this cause large interference because if there are no passwords then the user will be maximum and if user will be maximum then the traffic will be higher and contention can arise that will cause the interference. If we ignore the difficulties arising the in the unlicensed spectrum sharing it is very useful in the increase of users and the coverage area [1]. 3 SECONDARY SPECTRUM ACCESS The ratio of VHF/UHF wideband is used for the secondary spectrum access candidate, it is also called TV white spaces [4][5][6], it has been invented in recent times. But the effect of the interference which has been added from the nearby channels, that interference has not been under consideration, the interference from the entire channels combine and added to the path. The secondary spectrum opportunities for mobile and portable devices which combine with database of geo-locations. The evaluated opportunities in maximal secondary users that can reach the “TV white space” at the same time. There is a special band is given to the emphasis to protect the TV receiver from the interference caused from the adjacent channel and the channel path itself so that the transmission of the television is not effected from the interference. Suffering from the less number of users at the different locations, by using the process of optimization we can increase the number of secondary spectrum access users at two different locations very easily .If we look out to the characteristic of the interference in depth we can easily identified that the adjacent channel causes the really big threat in the process of TV channels and specially for those channels that has low transmitted power .If we really succeeded in the protection from the interference then the TV channels secondary spectrum access can be implemented to the very wider geographical area at the different locations. Today we are really known very well about that the use of wireless network is rapidly increasing and the wireless network providers are in the searching to increase the mobile and the broadband traffic. In the secondary spectrum we don’t really need very large spectrum and it is also under-licensed and can be efficiently used and it attracts the usage in the industry and for the education purposes. The UHF/VHF TV band are mostly considered as the secondary spectrum access candidates. The secondary users are in under considerations to the scientists, designing both optimized solutions and heuristic [8][9] algorithm and optimized solutions[10][11] for the transmitting of power from the different locations. Those researches are really stand us to calculate the interference and how to minimized that interference by optimizing, however the main aim of the scientists to minimize the co-channels interference for the TV secondary subscriber at the different
  4. 4. locations and at the very long distances from the source channel. The TV receiver which can be very effected to adjacent channel interferences (ACI) , this effect of co-channel interference can really do damage if the secondary subscriber transmitting to the power of the victim. The effect of the co-channels interference can be scenario based if the portable device and the secondary subscriber are in the dense populated areas where that the co-channels are located very close to each other and the effect of the co-channel interference will be maximum. The scientists are doing for the work of how we can combine the effect of these two types of interference is still in under processes. The phenomena of co-channel interference and adj-cha interference is shown in the following figure 3.1, figure 3.2, figure 3.3 and figure 3.4 below. Figure 3.1 Figure 3.2 Figure 3.3 Figure 3.4 A) PRIMARY SYSTEM Terrestrial TV network broadcasting that station can go about to the area of radius 30-50 km.The range of terrestrial system will be same either the TV receiver has an indoor antenna or the rooftop antenna. To avoid the interference between the two co-channels the nearby TV receiver has to be connected to the different subset of the channels to avoid the mutual interference [6][10][14]. However they are provided for secondary reuse. B) SECONDARY SYSTEM In the commercial point for reuse of ’TVWS’ are in under lies in the scenario to the heavily populated implemented short-range or other indoor system. So, the secondary system is in under study in the portable and mobile devices, to the low transmit power. The Wi-Fi system is the best example of this system. Secondary user can be implemented to either indoor or outdoor secondary system, transmitting with limited fixed power. c) COEXISTENCE DEPLOYMENT SCENARIOS The system which are described earlier (primary and secondary system) in the fig we can seen the portion A,B can be easily identified, receiver of TV is linked the indoor antenna. We can see in the figure clearly that the effect of co-channel interference will be greater on the portion A, however the receiver of both TV stations are located indoor. If we look out to the receiver part of which is connected to the roof-top antenna. The links are free from penetration loss of indoor
  5. 5. walls. The common channel interference is located at the roof-top so it will exhibit low interference as compared to the part b, because in the previous case both the antenna and the receiver located inside the height of the clutters. CONCLUSION Unlicensed spectrum bands have specified rules for sharing but there is no limit of the users in unlicensed spectrum sharing. There are two possible techniques to increase the system capacity for the unlicensed spectrum sharing which is in turn are Resource Allocation and the Self- Enforcing methods. Both methods increase the system efficiency, bandwidth, data rates which suits the system compatibility and the system enhancement. Licensed spectrum includes the sharing of dedicated frequency bands. Lenience of limited frequency band is allocated to the organizations which purchase them in bidding. The dedicated band of frequency is only permitted to be used by the concerned organization or user. Licensed spectrum is more secure and beneficent to use than unlicensed having less interference and secure communication. In secondary spectrum access we used two frequencies ultra-high frequencies and the very high frequencies to get the system spectrum access. We used co-channel interference technique in the secondary spectrum access which is adjacent channel interference to increase the use of same frequencies in the adjacent channels and we do not require the larger bandwidth in the secondary spectrum access. Using this, the major effect of interference will be minimize. REFRENCES [1]Unlicensed Spectrum Subcommittee Reprt,January 6, 2010 [2] M. Nekovee, “Quantifying the Availability of TV White Spaces Cog- nitive Radio Operation in UK,” in IEEE International Conference on Communications Workhops, Jun. 2009. [3] K. Harrison, S. Mishra, and A. Sahai, “How much white-space capacity is present?,” in IEEE International Symposium on Dynamic Spectrum Accesses Networks (DySPAN), Apr. 2009. [4] Federal Communications Commission, “In the Matter of Unlicensed Operation in the TV Broadcast Bands: Second Memorandum Opinion and Order,” Sept. 2010. [Online] Available: http://www.fcc.gov. [5] Ofcom, Digital Dividend: Geolocation for Cog- nitive Accesess,” Nov. 2009, [Online]. Available: http://stakeholders.ofcom.org.uk/consultations/cogaccess/. [6] ECC Report 159, ”Technical and Operational Requirements for the Possible Operation of Coginitive Radio Systems in the White Spaces of the Frequency Band 470- 790MHz,” Jan. 2011, [Online]. Available: http://www.ero.dk. [7] ECC Report 148, ”Measurements on the Performance of DVB-T Receivers in Presence Interference from Mobile Service (Especially from LTE)”, Jan. 2010, [Online]. Available: http://www.ero.dk. [8] J. van de Beek, J. Riihijarvi, A. Achtzehn, and P. Mahonen, “TV White Space in Europe,” IEEE Transactions on Mobile Computing, vol. 11, no. 2, pp. 178 –188, Feb. 2012. [9] R. Jantti, J. Kerttula, K. Koufos, and K. Ruttik, “Aggregate Interference FCC and ECC White Space Usage Rules: Case Study in Finland,” in IEEE International Symposium on Dynamic Spectrum Access Net- works (DySPAN), May 2011. [10] K. Ruttik, K. Koufos, and R. J¨antti, “Modeling of the Secondary System’s Generated Interference, Studying of Its Impact on Secondary System Design ,” Radio Engineering, vol. 18, no. 7, pp. 1271–1278, Dec. 2010. [11] Y. Sel´en, J. Kronander, “Optimizaing Power Limits for White Space Devices under a Probability Constraint on Aggregated Inteference,” submitted to the IEEE International Symposium on Dynamic Spectrum Accesses Networks (DySPAN), 2012. [12] E. Obregon, L. Shi, J. Ferrer, and J. Zander, “Experimental Verification of Indoor TV White Space Opportunity Prediction Model,” the Fifth International
  6. 6. Conference on Cognitive Radio Oriented Wireless Networks Communications (CROWNCOM), Jun. 2010. [13] H. Karimi, “Geolocation Databases for White Space Devices in the UHF TV Bands: Specification of Maximum Permitted Emissions Levels,” in IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks (DySPAN), May 2011. [14] Ericsson, 2013. Ericsson Mobility Report. Available at: http://www.ericsson.com/mobility-report/
  7. 7. Conference on Cognitive Radio Oriented Wireless Networks Communications (CROWNCOM), Jun. 2010. [13] H. Karimi, “Geolocation Databases for White Space Devices in the UHF TV Bands: Specification of Maximum Permitted Emissions Levels,” in IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks (DySPAN), May 2011. [14] Ericsson, 2013. Ericsson Mobility Report. Available at: http://www.ericsson.com/mobility-report/

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Licensed Spectrum sharing, Unlicensed Spectrum sharing and Secondary Spectrum Access

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