14th rio wireless alberto boaventura oi v1.0


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Intends to discuss about new data centric environment challenges due tsunami data traffic in mobile broadband and how industry is being prepared to address all of these changes.

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14th rio wireless alberto boaventura oi v1.0

  1. 1. 14th Rio Wireless Alberto Boaventura 2014-05-13 4G & Beyond Changes and Challenges
  2. 2. Changes and Challenges TELECOMM BECOMES MOBILE MOBILE BECOMES DATA DATA BECOMES VIDEO VIDEO BECOMES SOCIAL 0 200 400 600 800 1.000 2009 2010 2011 2012 2013 Smartphones Tablets Netbooks Notebooks Desktops Source: Morgan Stanley & Nomura 2012 WorldDeviceShipments(Millions) Source: Ericsson 2013 2009 2010 2011 2012 2013 1000 1800 Voice Data Total(UL+DL)traffic(PetaBytes) Source: Cisco VNI 2012 12 2012 2013 2014 2015 2016 2017 6 Mobile File Sharing Mobile M2M Mobile Web/Data Mobile Video Exabytespermonth In 2016, Social Newtorking will be second highest penetrated consumer mobile service with 2, 4 billion users – 53% of consumer mobile users - Cisco 2012 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 10 6 LTE UMTS/HSPA GSM;EDGE TD-SCDMA CDMA Other WorldMobileSub.(Billions) Source: Ericsson 2012 Voice Centric Data Centric Traffic Reveue 1 2 3 4 5 RAPID LIFE CYCLE M2M, NEW DEVICES & APPS.CUSTOMER EXPERIENCE TRAFFIC & REVENUE DECOUPLING
  3. 3. π‘ͺ 𝒃𝒑𝒔 ≀ 𝒆 βˆ™ 𝑩(𝑯𝒛) βˆ™ π’π’π’ˆ 𝟐 𝟏 + 𝑲 𝑺 𝑡 + 𝑰 π‘ͺ 𝒃𝒑𝒔 ≀ 𝒆 βˆ™ 𝑩(𝑯𝒛) βˆ™ π’π’π’ˆ 𝟐 𝟏 + 𝑲 𝑺 𝑡 + 𝑰 200 MHz/Operator 30 bps/Hz 1000 Mbps/km2 More Spectrum New Technologies Split Cells Changes and Challenges Release 99 Release 5 Release 8 Release 10 1 Mbps 10 Mbps 100 Mbps 1,000 Mbps 10,000 Mbps 2018 x1000 Mobile Broadband Growth
  4. 4. About Spectrum
  5. 5. Spectrum Requirement Spectrum Requirements per Operator (Rysavy Research – February 2010): The expectation is to be needed over than 200 MHz per operator in 2016. Band UL (MHz) DL (MHz) Width (*) WRC 3GPP (LTE) Anatel 450 MHz 451-457 461-468 14 MHz 2007 Band 31 Res 558/2010 700 MHz 703-748 758-803 90 MHz 2007 Band 28 Res 625/2013 850 MHz 824 - 849 869 - 894 25 MHz 2000 Band 5 Res 454/2006 900 MHz 898,5 - 901; 943,5 - 946 907,5 - 915; 952,5 - 960 10 MHz 2000 Band 8 Res 454/2006 1800 MHz 1.710-1785 1805-1880 150 MHz 1992/ 2000 Band 3 Res 454/2006 2100 MHz 1920-1975 2110-2165 110 MHz 2000 Band 1 Res 454/2006 2600 MHz 2500-2570 2620-2690 140 MHz 2007 Band 7 Res 544/2010 3500 MHz 3400-3600 (TDD) 200 MHz 2007 Band 42 Res 537/2010 Brazil: 330 MHz (Res 454/2006) and recently 204 MHz (Res 544/2010). But due CAP constraint, only 120-140 MHz per operator is allowed. οƒΌ Spectrum Aggregation οƒΌ Sensing and Cognitive radio technologies for spectrum sharing οƒΌ Offloading with fallback techniques to exclusive global bands, e.g. for mobility/roaming. οƒΌ ITU-R forecasts a need of 1280 to 1720 MHz in the medium term for IMT (before 2020) οƒΌ Global IMT spectrum of 715 MHz currently available, plus <300 MHz on a regional basis οƒΌ WRC’12 confirmed the intention to allocate more spectrum to IMT in the 700 MHz band (~90 MHz) οƒΌ FCC: Make 500 MHz of spectrum newly available for broadband within 10 years οƒΌ European Comm.: 1200 MHz (incl. exist. 625 MHz) to be allocated to mobile broadband by 2015 οƒΌ Need to consider shared spectrum: Unlicensed spectrum, unlicensed secondary usage or Licensed Secondary Access (LSA) e.g. in TV white space, WORLD SPECTRUM FORECAST SPECTRUM PER OPERATOR SPECTRUM IN BRAZIL LICENSED SPECTRUM NEW SPECTRUM NEW TECHNOLOGIES FOR SPECTRUM MANAGEMENT ITU-R M.2078 projection for the global spectrum requirements in order to accomplish the IMT-2000 future development, IMT-Advanced, in 2020. 531 MHz 749 MHz 971 MHz 749 MHz 557 MHz 723 MHz 997 MHz 723 MHz 587 MHz 693 MHz 1027 MHz 693 MHz Region 1 Region 2 Region 3
  6. 6. CARRIER AGGREGATION IN DETAIL SCENARIOS REQUESTED CA WIS Spectrum Flexibility 20 MHz 15 MHz 10 MHz 5 MHz 3 MHz 1,4 MHz UL DL Frequency FDD DL UL Time TDD In 3GPP Release 12 defines 43 Band schemes to LTE Intra & Inter Band Band X Band y DIFFERENT BANDWIDTHS TDD & FDD SUPPOORT SEVERAL SUPPORTED BANDS CARRIER AGGREGATION PCell SCell PDCCH/PDSCH/PUSCH Dynamically activated/deactivated for UE battery saving Rel-10 UE has one PCell (UE specific) and may have up to 4 SCell PDCCH/PDSCH/PUSCH/PUCCH Measurement, mobility TAU procedures οƒΌ Carrier aggregation Support wider bandwidth οƒΌ Two or more component carriers οƒΌ Up to 100MHz and for spectrum aggregation οƒΌ Each component carrier limited to a maximum of 110 RBs οƒΌ Carrier aggregation type: Contiguous; Non- contiguous F1 F2 F1 and F2 cells are co-located but different azimuth F1 = F2 or F1 ο‚Ή F2 Scenario 1 F1 and F2 overlaid & Same coverage F1 = F2 Scenario 2 F1 and F2 overlaid,, but F2 has smaller coverage F2> F1 Scenario 3 Similar to scenario #2, but frequency selective repeaters are deployed so that coverage is extended for one of the carrier frequencies Scenario 4 F1 provides macro coverage and on F2 Is used to hot spots F2>F1 Scenario 5 Requester/Rapourter Bands China Telecomm B1,B7 TeliaSonera B3, B7 Rogers B4,B7 China Unicom B7,B7 Vodafone B3, B20 Huawei (Orange) B3, B20 Vodafone B8, B20 Cox B4, B12 US Cellular B5, B12 Ericsson (Verizon) B4, B13 AT&T B2, B17 AT&T B4, B17 AT&T B5, B17 Sprint B25, B25 Huawei (CMCC) B38, B38 Clearwire B41, B41
  7. 7. About New Technology
  8. 8. Spectral Efficiency 0 1 2 3 4 5 6 7 200kHz 25 TRX 3,84MHz 1 WCDMA Carrier r R D i j i jD r R D i j i jD Codec FR D = 4 / Sector = 3 Reuse = 4 x 3 #Ckt/Sector= 2x7=14 Codec AMR 12.2 127 Walsh Codes Reuse = 1 %SHO=20% #Ckt/Sector = 64 24 Erl/BTS 160 Erl/NodeB r R D i j i jD PRBs ... 7Symbols 12 subcarriers 25 Resource Blocks 700 Erl/eNBCodec AMR 12.2 25 PRBs - 300 REs 200 -250 users/ Sector 2G (GSM) 3G (UMTS/HSPA) LTE HSPA+ 2100 MHZ VS LTE 2600 MHZ 3G (UMTS/HSPA) LTE Voice Capacity @ 5 MHz Data Capacity @ 5 MHz Source: Brendan McWilliams, Yannick Le PΓ©zennec, Grahame Collins Vodafone Technology Networks, Access Competence Centre, Madrid, Spain & Newbury, United Kingdom 2012 𝑻𝒉𝒓 = #π‘ͺ𝒐𝒅𝒔 Γ— 𝑴𝒐𝒅 Γ— 𝑭𝑬π‘ͺ Γ— πΆβ„Žπ‘–π‘π‘…π‘Žπ‘‘π‘’ 𝑺𝑭 𝑻𝒉𝒓 = πŸπŸ“ Γ— πŸ” Γ— 𝟏 Γ— πŸ‘, πŸ–πŸ’ πŸπŸ” = 𝟐𝟏 𝑴𝒃𝒑𝒔 𝑻𝒉𝒓 = #π‘΄π‘°π‘΄πŸŽ Γ— #𝑹𝑩𝒔 Γ— 𝑴𝒐𝒅 Γ— 𝑭𝑬π‘ͺ Γ— #π‘ͺ𝒂𝒓.Γ— #π‘Ίπ’šπ’Žπ’ƒ 𝑻𝑻𝑰/𝟐 𝑻𝒉𝒓 = 𝟐 Γ— πŸπŸ“ Γ— πŸ” Γ— 𝟏 Γ— 𝟏𝟐 Γ— πŸ” βˆ’ 𝟏𝟐 𝟎, πŸ“ = πŸ‘πŸ” 𝑴𝒃𝒑𝒔 MIMO Yes, but not for existing network Modulation QPSK, 16 QAM, 64 QAM Intereference Rake Receiver Limitation Up Link limitation due interference MIMO Yes, Modulation QPSK, 16 QAM, 64 QAM Intereference FRF/ICIC Limitation CoMP/ICIC/e-ICIC Hundreds of users per NodeB Thousands of users per eNB
  9. 9. Multiple Input, Multiple Output (MIMO) MCS, PMI, RI CQI, PMI, RI CRS Closed loop, codebook precoding MCS CQI CRS, DRS Open loop, non-codebook precodingTM Transmission scheme of PDSCH CQI mode Mode 1 Single-antenna port CQI Mode 2 Transmit diversity CQI Mode 3 Open-loop spatial multiplexing CQI Mode 4 Closed-loop spatial multiplexing CQI, RI, PMI Mode 5 Multi-user MIMO CQI, PMI Mode 6 Closed-loop Rank=1 precoding CQI, PMI Mode 7 Beamforming Single- antenna port; port CQI Mode 8 Dual layer beamforming CQI, RI, PMI Mode 9 Switching SU & MU- MIMO till 8 CQI, RI h11 h12 h21 h22 𝒀 = 𝒉 𝟏𝟏 𝒉 𝟏𝟐 𝒉 𝟐𝟏 𝒉 𝟐𝟐 𝑿 + 𝑡 SNR BER π‘ͺ 𝒃𝒑𝒔 ~𝑩(𝑯𝒛) βˆ™ π’π’π’ˆ 𝟐 𝟏+, π’Žπ’Šπ’(𝑴 𝑻𝒙, 𝑴 𝑹𝒙) βˆ™ 𝑺𝑡𝑹 min(MTx , MRx) Antenas Capacidade π‘ͺ 𝒃𝒑𝒔 ~, π’Žπ’Šπ’(𝑴 𝑻𝒙, 𝑴 𝑹𝒙) βˆ™ 𝑩(𝑯𝒛) βˆ™ π’π’π’ˆ 𝟐 𝟏 + 𝑺𝑡𝑹 BASIC IDEA MULTIPLEXING DIVERSITY BEAMFORMING 1=0ΒΊ 1=45ΒΊ 30 210 60 240 90 270 120 300 150 330 180 ... p1 p2 pN  TRANSMISSION MODE CLOSED/OPEN LOOP MU-MIMO FD-MIMO οƒΌ Individual streams are assigned to various users, οƒΌ Particularly useful in the uplink because the complexity on the UE side can be kept at a minimum by using only one transmit antenna. οƒΌ Users separated by spatial signatures οƒΌ Spatial signatures are typically not orthogonal οƒΌ May require interference reduction (MUD, cancellation, etc.) h11 h12 h21 h22 οƒΌ Improved beamforming capability (vertical and horizontal active beamforming) οƒΌ Improved system capacity οƒΌ Easy adaptation to traffic and UE population change οƒΌ Flexible partitioning of antenna resource for coverage and capacity 4x 3x 2x 1x Capacity Coverage 𝒁 = 𝒑 𝑯 βˆ™ 𝑿
  10. 10. Active Antenna System (AAS) Advanced BS platform with optimized structure, cost, and performance features that meet operator requirements for mobile broadband (MBB) services. A principal advantage of active antennas is their ability to create and steer beams within the cell. AAS 1=0ΒΊ 1=45ΒΊ 30 210 60 240 90 270 120 300 150 330 180 ... p1 p2 pN  Beamforming works by changing the phase and relative amplitude of the signal emitted from each radiating element, to create constructive or destructive interference. BEANFORMING Rx2 Rx1 Cell2 Cell1 f2 f1 Rx Tx GSM LTE SEGREGATED UE BEAM STEERING FLEXIBLE RX DIVERSITY VERTICAL/HORIZONTAL CELL SPLIT SEPARATE RX-TX TILTING SEPARATE IRAT TILTING SEPARATE CARRIER TILTING
  11. 11. About Split Cell
  12. 12. SMALLCELLS & HETNET High Traffic Density 0,0 Mbps/km2 100,0 Mbps/km2 200,0 Mbps/km2 300,0 Mbps/km2 400,0 Mbps/km2 500,0 Mbps/km2 0,3 km0,4 km0,5 km0,6 km0,7 km Coverage Capacity 2015 156% 156% Capacity 2016 2014 2015 2016 2013 οƒΌ Downlink: Terminal camped on in macro is interfered by a small cell. And terminal served by a small cell to connect the edge of cell will be interfered by the macro cell. οƒΌ Uplink : one terminal connected in macro and close to the cell border creates strong interference in a small cell next. And large number of connected terminals in small cells generate uplink interference in the macro cell. οƒΌ They both are addressed with sophisticated mechanisms like ICIC, e-ICIC and CoMP οƒΌ IP Access (MPLS-TP, Metro Eth, MDU) , Giga-Ether over 150 Mbps per BTS οƒΌ Required necessarily optical fiber, but Radio NLOS can be alternative for higher capillarity οƒΌ New synchronism support (IEEE 1588, SyncE) οƒΌ For CoMP, Latency must be below 1 ms οƒΌ New interface other than IP: CPRI οƒΌ Mobility device in idle state impacts the relative load between layers and battery consumption and frequency of handovers. οƒΌ Increase in handovers due to the small size of the cells increases the risk of dropped calls (Dropped Call Rate), οƒΌ Devices in connected state may need to HO to a small cell and, if they are on different frequencies, will need efficient scheme discovery of small cell that minimizes the impact on battery consumption. οƒΌ Traffic/Capacity balancing with several resources and frequencies οƒΌ Small cell radius of coverage is reduced compared to macro, it is necessary to locate accurately the traffic sources; οƒΌ Site acquisition: Given the limitation on the scope of the small cell, you have to know exactly where the traffic is generated and get the rights to install that exact spot. οƒΌ New types of leases should be developed. οƒΌ The way to optimize and operate should fit depending less manual intervention. Resources SON (Self Organizing Networks) will be important to maintain a good performance. CPRI Core Network BBU 1 BBU N BBU Hotel & C-RAN LIPA/SIPTO Local Cache ... Firewall Interference Control features, like: ICIC , e-ICIC and CoMP and local offload traffic TRAFFIC DESNIFICIATION Stadium, arenas and high density traffic places coverage for capacity improvement INTERFERENCE MITIGATION BACKHAUL MOBILITY MANAGEMENT OTHERS
  13. 13. ICIC (Inter Cell Interference Coordination) 3GPP Release 8 οƒΌ Limited frequency domain interference information exchange οƒΌ Primarily to help cell edge UEs οƒΌ Involves coordination between neighboring eNBs Using the X2 interface οƒΌ ICIC related X2 messages are defined in standard A eNB can use information provided by neighboring eNB During its scheduling process οƒΌ Static and limited coordination ICIC (INTER CELL INTERFERENCE COORDINATION) E-ICIC (ENHANCED ICIC) FE-ICIC (FURTHER ENHANCED ICIC) HII (schedule RBX) OI (Hi interference RBy) X2 RBX RNTP (High power RBx) X2 RBX 3GPP Release 10 οƒΌ Dynamic time domain interference coordination Based on Almost Blank Subframes (ABS) οƒΌ ABS carries no data, only essential control information, οƒΌ Since most REs are blank (zero power), interference is reduced. οƒΌ In macro-pico setup with CRE, macro is the aggressor and pico is the victim ABS Protected Subframe Aggressor Cell Victim Cell X2 Aggressor Cell Victim Cell Identifies interfered UE Requests ABS Configures ABS ABS Info Measurement Subset Info Uses ABS and signals Patern X2 3GPP Release 11 οƒΌ Enhanced transceiver signal processing for ABS οƒΌ Reduced power ABS οƒΌ Rx based Puncturing οƒΌ Rx based Interference Cancellation οƒΌ Tx based Muting οƒΌ Reduced Power ABS X2 Victim Cell P1 P2 Reduced Power ABS allows macro improving performance by reducing power in subframe without zero power for cell center macro UE. Zero Power ABS Reduced Power ABS X2 F1 F2 F3
  14. 14. Coordination Multi Point (CoMP) h11 h12 h21 h22 𝒀 = 𝒉 𝟏𝟏 𝒉 𝟏𝟐 𝒉 𝟐𝟏 𝒉 𝟐𝟐 𝑿 + 𝑡 οƒΌ Defined since Release 10 οƒΌ Fundamental tool for increasing capacity οƒΌ Modes:  Coordinated scheduling & Beamforming  Joint processing/transmission h11 h12 h21 h22 𝒀 = 𝒉 𝟏𝟏 𝒉 𝟏𝟐 𝒉 𝟐𝟏 𝒉 𝟐𝟐 𝑿 + 𝑡 X2 οƒΌ By coordinating transmission and reception across geographically separated locations (points) it is possible to enhance network performance οƒΌ This includes coordinated scheduling and beamforming as well as joint reception οƒΌ Full performance requires baseband connection between points Coordinated Scheduling & Beamforming X2 Join Processing Coherent transm. & Non-Coherent transm. Instantaneous Cell Selection Intra-cell CoMP Inter-cell CoMP X2 Smallcells When the terminal is in the border may receive signal from multiple stations in a coordinated manner Effective interference control between cells (inter-cell inerference)) Heterogeneous Network οƒΌ Intra-Cell CoMP οƒΌ Inter-Cell: Higher RRH CoMP οƒΌ Inter-Cell: Lower RRH CoMP MIMO + SON = COMP MIMO (CO-LOCATED TRANSMISSION) DOWNLINK COORDINATED MULTIPOINT OPERATION MODES 3GPP TS 36.813 SCENARIOS data
  15. 15. About Future
  16. 16. LTE Advanced ITU-R M.2034 Spectral Efficiency DL 15 bits/Hz UL 6.75 bits/Hz Latency User Plane < 10 ms Control Plane < 100 ms Bandwidth ITU-R M.2034 40 MHz ITU-R M.1645 100 MHz ADVANCED Coverage Capacity SmallCells High order MIMO Carrier Aggregation Hetnet/CoMP LTE LTE –A 3GPP TR 36.913 3GPP Release 8 3GPP Release 10 RELEASE 8/9 RELEASE 10/11 RELEASE 12/13 20 MHz OFDM SC-FDMA DL 4x4 MIMO SON, HeNB Carrier Aggregation UL 4x4 MIMO DL/UL CoMP HetNet (x4.33) MU-MIMO (x1.14) Small Cells Enh. CoMP Enh. FD-MIMO (x3.53) DiverseTraffic Support LTE Roadmap Carrier Aggregation Intra & Inter Band Band X Band y Multihop Relay Multihop Relay Smallcells Heterogeneous Network Colaboration MIMO (CoMP) e HetNet High Order DL-MIMO & Advanced UL-MIMO C-plane (RRC) Phantom Celll Macro Cell F1 F2 F2>F1 U-plane D2D New Architecture
  17. 17. METIS PROJECT PREMISES (SOURCE: ETSI/ERICSSON) METIS: 29 PARTNERS 5G Vision and Timeframe ITU-RΒ΄s docs paving way to 5G: IMT.VISION (Deadline July 2015) - Title: β€œFramework and overall objectives of the future development of IMT for 2020 and beyond” Objective: Defining the framework and overall objectives of IMT for 2020 and beyond to drive the future developments for IMT IMT.FUTURE TECHNOLOGY TRENDS (Deadline Oct. 2014) To provide a view of future IMT technology aspects 2015-2020 and beyond and to provide information on trends of future IMT technology aspects EU (Nov 2012) China (Fev2013) Korea (Jun 2013) JapΓ£o (Out 2013) 2020 and Beyond Adhoc Exploratory Research Pre-standardization Standardization activities Trials and Commercialization 2012 2013 2014 2015 2016 2017 2018 2019 2020 WRC15WRC12 WRC19 Mobile and wireless communications Enablers for the Twenty-twenty Information Society
  18. 18. METIS SCENARIOS AND TEST CASESHORIZONTAL TOPICS Technical Solutions Device-to-Device (D2D) Ultra Reliable Communications (URC) Ultra Dense Networks (UDN) Moving Networks (MN) Massive Machine Communications (MMC) Unique Expertise allowing to οƒΌ Conduct fundamental research at early point οƒΌ Identify where a revolution or evolution from LTE-A is needed Concepts & Technology solutions for β€œ5G” to οƒΌ Meet diverse requirements of future services οƒΌ Connect diverse devices οƒΌ Support 1000 X traffic increase Consensus & Global strategy to οƒΌ Ensure leadership in future communications system οƒΌ Ensure early global consensus About METIS Mobile and wireless communications Enablers for the Twenty-twenty Information Society Source: http://www.metis2020.com/ Lay the foundation & Ensure a global forum & Build an early global consensus for beyond 2020 β€œ5G” mobile & wireless communications Efficiency to allow for a constant growth in capacity at acceptable overall cost and energy dissipation Scalability to respond to a wide range of requirements regardless of the traffic amount (low or high) Versatility to support a significant diverse requirements (Availability, Mobility, QoS) and use cases
  19. 19. 5G Potential Technologies 1=0ΒΊ 1=45ΒΊ 30 210 60 240 90 270 120 300 150 330 180 ... p1 p2 pN  οƒΌ Native M2M support οƒΌ A massive number of connected devices with low throughput; οƒΌ Low latency οƒΌ Low power and battery consumption hnm h21 h12 h11 οƒΌ Higher MIMO order: 8X8 or more οƒΌ System capacity increases in fucntion of number of antennas οƒΌ Spatial-temporal modulation schemes οƒΌ SINR optimization οƒΌ Beamforming οƒΌ Enables systems that illuminate and at the same time provide broadband wireless data connectivity οƒΌ Transmitters: Uses off-the-shelf white light emitting diodes (LEDs) used for solid-state lighting (SSL); οƒΌ Receivers: Off-the-shelf p-intrinsic-n (PIN) photodiodes (PDs) or aval anche photo-diodes (APDs) C-plane (RRC) Phantom Celll Macro Cell F1 F2 F2>F1 U-plane D2D οƒΌ Phantom Cell based architecture οƒΌ Control Plane uses macro network οƒΌ User Plane is Device to Device (D2D) in another frequency such as mm-Wave and high order modulation (256 QAM). Net Radio Core Cache οƒΌ Access Network Caching οƒΌ Network Virtualization Function οƒΌ Cloud-RAN οƒΌ Dynamic and Elastic Network οƒΌ Universal Filtered Multi-Carrier (UFMC) : Potential extension to OFDM ; οƒΌ Filter Bank Multi Carrier (FBMC): Access sporadic, short bursts, increased robustness, support QAM ​​symbols and minimization problems offset; sustainability fragmented spectra. οƒΌ High modulation constellation MASSIVE MIMO SPATIAL MODULATION COGITIVE RADIO NETWORKS VISIBLE LIGHT COMMUNICATION DEVICE-CENTRIC ARCHITECTURE NATIVE SUPPORT FOR M2M CLOUD NETWORK & CACHE NEW MODULATION SCHEME 5G Non-Orthogonal Waveforms for Asynchronous Signalling (5GNOW) οƒΌ New protocol for shared spectrum rational use οƒΌ Mitigate and avoid interference by surrounding radio environment and regulate its transmission accordingly. οƒΌ In interference-free CR networks, CR users are allowed to borrow spectrum resources only when licensed users do not use them.
  20. 20. Alberto Boaventura alberto@oi.net.br +55 21 98875 4998 THANKS! OBRIGADO!