Lecture 5 – November 2, 2020 Wireless Access Graduate course in Communications Engineering University of Rome La Sapienza Rome, Italy 2020-2021
Cognitive radio and networks
Outline What is Cognitive Radio and why using it Regulation of Cognitive Radio Cognitive radio in 5G networks
What is Cognitive Radio The term “ Cognitive Radio ” was coined by Joseph Mitola in an article published in 1999 What is Cognitive Radio? A Cognitive Radio “ is a radio frequency transmitter/receiver that is designed to intelligently detect whether a particular segment of the radio spectrum is currently in use, and to jump into (and out of, if necessary) the temporarily-unused spectrum very rapidly, without interfering with the transmission of other authorized users ” A Cognitive Radio “ is self-aware, user-aware, RF-aware, and incorporates elements of language technology and machine vision ” Ref : J. Mitola et al., “ Cognitive radio: Making software radios more personal, ” IEEE Pers. Commun., vol. 6, no. 4, Aug. 1999
What is Cognitive Radio The concept of a Radio capable of adapting to the environment and of adjusting transmission parameters according to internal and external unpredictable events is very appealing in the wireless world The final goal remains to form wireless networks that cooperatively coexist with other wireless networks and devices
What is Cognitive Radio External A Cognitive Radio can be Stimuli defined as a wireless system that is aware of the surrounding environment Cognitive By sensing the outside world, a Cognitive Radio Radio learns from the environment and adapts its behaviour accordingly E x t e r S n t i a m l u l i
What is Cognitive Radio Awareness Efficiency Cognitive Standard Learning R e l i a b i l i t y Radio Radio R e e c o c n n f e i g g u i r l a l e b t i l n i t I y
What is Cognitive Radio A Cognitive Radio behaves according to five main actions: Cognitive Radios are aware of their OBSERVE surrounding environment Cognitive Radios evaluate among PLAN several strategies Cognitive Radios are always capable DECIDE to select one strategy of operation Cognitive Radios can enrich experience LEARN by forming new strategies Cognitive Radios perform ACT communication according to the selected strategy
What is Cognitive Radio Spectrum access , spectrum efficiency , and spectrum reliability have become critical policy issues during the last years. Increasing growth of wireless services (3G cellular systems, Wi-Fi, Wireless Internet…) Growing demand for spectrum-based communication links (businesses, consumers, government…) Approval of unlicensed wireless transmissions (UWB) and LTE-U
Regulation of Cognitive Radio In May 2003 , the FCC recognizes Cognitive Radio as a way to dramatically improve the efficiency of spectrum use Advances in technology are creating the potential for radio systems to use spectrum more intensively and more efficiently than in the past Cognitive radio technologies have the potential to provide a number of benefits that would result in increased access to spectrum and also make new and improved communication services available to the public. Ref : FCC, NOTICE OF PROPOSED RULE MAKING AND ORDER In the Matter of Facilitating Opportunities for Flexible, Efficient, and Reliable Spectrum Use Employing Cognitive Radio Technologies , ET Docket No. 03-108, December 30, 2003
Regulation of Cognitive Radio In the 2003 document, the FCC identifies four possible scenarios for Cognitive Radios 1 A licensee employs cognitive radio Licensed technologies internally within its own Networks network to increase efficiency of use of the radio resource Example: Cognitive Cellular Networks Adaptive Cognitive Modulation Base Station Dynamic Cognitive Frequency Base Station Selection Transmit Power Control
Regulation of Cognitive Radio In the 2003 document, the FCC identifies four possible scenarios for Cognitive Radios 2 A licensee and third party sign an agreement allowing Secondary secondary spectrum uses for cognitive radio devices Markets Example: Public Primary Safety Leasing Network Cognitive devices operate on the channels that are Headquarter designated as available by the The public safety licensee and avoid licensee may operation on any f o reclaim access to k other frequency r o w t e N y r a d n o c e s its licensed e S c i v e D e v i t n i g o C spectrum at any time
Regulation of Cognitive Radio In the 2003 document, the FCC identifies four possible scenarios for Cognitive Radios Coordination 3 Multiple licensed services can operate in the of Licensed same frequency bands by coordinating their use to avoid mutual interference Operation Example: Coexisting Networks k r k o r w o w t e Devices in the two t N B e N A networks gather information about spectrum utilization and perform an automated waveform selection
Regulation of Cognitive Radio In the 2003 document, the FCC identifies four possible scenarios for Cognitive Radios Non-voluntary 4 third party Unlicensed Cognitive devices operate at times and locations where licensed access spectrum is not in use Example: Rural Markets & Unlicensed Devices Rural Area Urban Area TV Station High-Power unlicensed operation (above Part 15 limit) Low-Power unlicensed operation (under Part 15 limit)
CR and coexistence: towards a new communication paradigm • Modelling and designing the access might not be limited to managing and controlling the resource within a network • Future wireless networks will include the possibility of coordinating access among different systems based on the coexistence paradigm – We refer to both intra and inter-system coexistence • Coexistence will introduce completely new features and structures within both terminals and network agents
Cognitive radio and coexistence: the ISM band • The problem of spectrum sharing has been (partially) addressed for wireless systems working in the Industrial Scientific and Medical (ISM) band • Systems working in this band include: – 802.11 (WiFi) – 802.15.1 (Bluetooth) – 802.15.3 • Older systems (WiFi, Bluetooth) do not See lecture on interference define any technique for coexistence and thus they interfere with one another • When 802.15.4a was defined (2007) techniques for DAA (Detect And Avoid) were imposed
Cognitive Radio and coexistence: the Ultra Wide Band case ! ! ! ! ! z H G 7 . . . . g n i y p u c c o l a n g i s a f o y d u t s e s a c e h T Given their ultra wide bandwidth, Ultra Wide Band (UWB) radio signals must in principle coexist with other radio signals. GSM 802.11a 802.11b/g UMTS PSD Bluetooth UWB frequency 0.9GHz 1.8GHz 2.4GHz 5GHz
Recent advances in regulation • Digital dividend : the benefit deriving from the switch off of analogue TV broadcasting signals in favour of digital, and the consequent release of radio spectrum • Spectrum resulting from digital dividend can be allocated to new broadband services • Example: Italy – Frequencies available in the 800, 1800, 2000 and 2600 MHz were assigned in a public bid in September 2011 – Total income: 3.2 billion – Frequencies were allocated based on a exclusive rights approach with a caveat: sharing based on cognitive radio can be allowed by a future regulation • What about frequencies reserved to Digital Terrestrial Television?...TV White Spaces
Recent advances in regulation • FCC frees up vacant TV airwaves for “Super Wi-Fi” technologies (September 2010) • Example of scenario #4 ( Non-voluntary third party access )
FCC rules for TV white spaces access • Access to TV Bands is granted based on the geographical position of the cognitive device • Each cognitive device must satisfy the following requirements: 1. Geo-location capability with positioning error < 50 m 2. Internet access capability • A cognitive device will adopt the following procedure before starting transmission: 1. Determine its own position (at switch-on time and then every 60 seconds) 2. Connect to a remote database and download list of available (that is: not used) TV channels (every 48 hours or every time its position changes by more than 100 m) 3. Select an available channel and start transmitting • Note: Spectrum sensing is not mandatory
TV White Spaces in Europe • Discussion on TV White Spaces has been ongoing for a while in Europe • Initial studies suggested that White Spaces are potentially numerous across Europe: • European Conference of Postal and Telecommunications Administrations (CEPT) Group SE43 has been working towards a regulation for White Spaces: - ECC Report 159 on Technical and operational requirements for the operation of cognitive radio systems in the band 470-790 MHz published by CEPT Group SE43 in January 2011
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