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Specialist user expectations. Present two way radio technologies. European VHF Two way radio and TV allocations. European UHF Two way radio and TV allocations. US UHF Two way radio and TV allocations. Global Cellular. Over 800 MHz of cellular bandwidth - the Deci band Handset. 1800 MHz.
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Global Cellular Over 800 MHz of cellular bandwidth - the Deci band Handset
1800 MHz 900 MHz 1900 MHz (US) UMTS 800 MHz 60 MHz E-GSM 35 MHz Base Rx E-GSM 35 MHz Base Tx 75 MHz Base Rx 75 MHz Base Tx 60 MHz 60 MHz 60 MHz AMPS/CDMA /TDMA 25 MHz Base Rx AMPS/CDMA /TDMA 25 MHz Base Tx 880 - 915 925 - 960 1710 - 1785 1805 - 1880 1850 - 1910 1930 - 1990 1920 - 1980 2110 - 2170 824 - 849 869 - 894 921 - 925 GSM-R 876 - 880 GSM-R 45 MHz Duplex Spacing 95 MHz Duplex Spacing 80 MHz Duplex Spacing 190 MHz Duplex Spacing 45 MHz Duplex Spacing 1900 - 1920 IMT2000TC (1880 - 1900 presently used for DECT) 2010 - 2025 IMT200TC 20 MHz Guard Band 20 MHz Guard Band 20 MHz Guard Band 30 MHz Guard Band SMR/ PMR Quin Band Device duplex bands
Duplex spacing and the duplex gap • Duplex spacing TX/RX separation within the handset • Duplex gap – separation between different mobiles or between a mobile and a DVB or ATSC portable receiver Duplex spacing
Issues with UHF in Europe • No coordinated approach to band allocations by country and by region in the UHF band. • Differences in present and future digital TV channel allocations which taken globally can be anywhere in the UHF band between 470 and 862 MHz. • Role of TV and public broadcasting in Public Safety and Disaster Recovery – present ITU initiatives • Nee for integration with other radio systems including cellular
TV channels • TV channels are transmitted at relatively high power. This potentially creates interference into proposed LTE receive bands • TV tuners need to tune across the whole UHF band. Present radio tuner architectures deliver poor sensitivity and the devices are vulnerable to interference from other transmissions including mobile cellular handsets.
Extended band plan to allow LTE handsets to receive and demodulate terrestrial broadcast channels anywhere in the UHF band Spain is still out in the cold as digital TV is implemented in Channels 67 to 69.
Extended band plan to allow LTE handsets to be used throughout Europe and ROW with simultaneous terrestrial broadcast receive functionality
Benefits to the broadcast community • Present terrestrial broadcast receivers have poor sensitivity, of the order of between -92 and -98 dBm, and are vulnerable to front end compression and inter modulation. • Sub banding will result in a terrestrial broadcast receiver that has the same or similar sensitivity and dynamic range as an LTE transceiver of an equivalent bandwidth. Note that 5 MHz UMTS transceivers presently have sensitivities that can exceed -120 dBm. • This means that users will be able to receive terrestrial broadcasts on portable receivers provided received signal strengths are similar to UHF LTE. This potentially includes HDTV transmissions.
Radio planning implications • Significant implications for future terrestrial broadcast and LTE radio planning and consolidates the present thinking that re broadcasting terrestrial broadcast signals from cellular sites may be sensible for all parties concerned.
Scale economy issues • The scale economies achievable from such a device combined with the incremental user value realisable from an LTE transceiver with integrated terrestrial broadcast receive capabilities would justify substantial engineering optimisation effort.
Cost and complexity • It could be expected that a Universal UHF LTE transceiver would work at least as well and have similar component costs to an LTE 900, 1800, 1900, 2100 device. • Component commonalities between a UHF LTE handset and LTE850 may deliver additional benefits.
The US and Mobile ATSC? • Broadcasters have indicated they would like the opportunity to announce new ATSC-based mobile and handheld broadcast services before the close of analog services in February 2009. • The planned work schedule for a mobile/handheld solution, therefore, is based on this premise. • The target dates for completion of the standards documentation are intended to take into account the time needed for professional and consumer manufacturers to develop equipment for implementation before such services can be introduced. • This emphasizes the need for the standards work to be completed as soon as possible.
Mobile ATSC? • The ATSC-M/H system will enable modes of operation that allow mobile reception by devices permanently mounted in cars, buses, and trains, at speeds up to at least 75 mph. • The system will support modes of operation that allow reception by handheld devices that are stationary or moving at walking speeds of about 3 mph (5 km/h).
US Upper band UHF Note second harmonic effect at 787.5 MHz potentially compromises GPS receive at 1575 MHz
Enabling technologies RF MEMS • Tuneable capacitors – tuneable antennas • Complex low insertion loss switch matrices • Tuneable resonators • Tuneable low noise high Q oscillators • These multiple functions need to be inter matched across a wide (widening) range of operational conditions • Need to be manufactured and packaged to meet aggressive production requirements
Murata SAW diplexer and SAW duplexer for the 1.7 GHz UMTS Band in Japan Adding filters to a handset design and/or increasing handset performance in terms of out of band rejection and in band signal handling capabilities adds cost, occupies board real estate, may add height ( critical in ultra thin handsets) and may have availability (time to market and product choice) implications.http://www.murata.com/ninfo/nr0581e.html
UHF handset design Summary • UHF design challenge for duplex spaced cellular has to be considered in the context of already complex and ambitious multi band requirements • UHF has special design requirements – high power TV in all markets, high power TV and high power public safety radio in some markets • Vulnerable portable TV receivers • Other vulnerable users for example Programme Making and Special Events in the UK in Channel 69 • Disconnects of the spectral auction and allocation process can be papered over by brute force technology solutions in the handset • This adds cost and complexity • Complexity adds to NRE costs and availability issues (time to market delay and product choice)
TDD as an option? • TDD as an alternative option • GSM half duplex proven and cost effective • Small additional step to move to full TDD • With TDD you trade network time domain complexity and density against simpler handset design. • To resolve the TDD network timing issues you would probably need to implement a UHF TDD network at a 2 GHz network density for example using existing 2 GHz cell sites • This would (probably) achieve higher data rates and the data rates could be maintained to the edge of each cell. • Handsets would be lower cost and simpler – 30 dollar rather than 300 dollar BOM for specialist radio equipment. • Basis for the TDD LTE UHF proposition. • This has not been taken fully into account in the LTE standards process. • TDD shifts frequency domain complexity in the handset into time domain complexity in the network - a frequency to time domain transform.
