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Tx spectral masks for mixed mode (adaptive modulation). ETSI standards for P-MP. Current multipoint (MP) standards in Europe specified by a number of ETSI EN’s . New Multipart standard DEN/TM 4130.
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ETSI standards for P-MP Current multipoint (MP) standards in Europe specified by a number of ETSI EN’s
New Multipart standard DEN/TM 4130 The new draft multipart standard 4130 seeks to combine the separate MP standards for all frequencies up to 33GHz into one. Drafted by STF208. < 1 GHz 1 – 3 GHz Multipart Standard 4130 3 - 11 GHz 24 - 29 GHz 31 - 33 GHz
Tx spectral masks in MP standards Masks designed according to 3rd-order intermodulaton / net filter discrimination (NFD) for like systems operating in adjacent channels e.g. in 3 – 11 GHz band:
Mixed mode (adaptive modulation) Current standards developed for P-P, terrestrial microwave systems, traditionally use a single modulation scheme (single mode). New generation of NLOS, P-MP systems often have adaptive modulation, (mixed mode), e.g. dynamically switch from QPSK -> 16QAM -> 64QAM depending on SNR and channel conditions for each subscriber. Question: What happens to the Tx spectral mask in mixed mode ? Current standards are inconsistent for mixed mode ……..
Inconsistencies in current standards } 1 mask < 1 GHz Mixed mode not applicable 1 – 3 GHz 1 mask Single-mode masks, but silent on mixed mode 3 - 11 GHz Multipart Standard 4130 ????? 24 - 29 GHz Mixed mode must use most stringent mask (except if guardband exists)
Possible Proposals Rapporteur for new Miscellaneous Work Item MI/TM-4162 in WP2 of ETSI TM4 must present a proposal and justification to ETSI for Tx spectral masks (mixed mode) in the multipart standard DEN/TM-4130. • Ideas for Proposals • Specify least stringent mask in mixed mode, but advise that the option • to use tighter mask is also provided to help operators with interference. • Specify default option as most stringent mask, but allow optional mode • with a relaxed mask to help manufacturers meet the spec. • Specify that the mask must change dynamically with the modulation. • Allow any Tx mask to be used within the block allocation, provided that • the block edge mask is not exceeded.
Conclusions • Mixed mode Inconsistencies need to be resolved in new draft standard 4130 • Must be finalised by December 2003 to be included in 4130 • Comments / suggestions / proposals to : • Malcolm Sellars msellars@cambridgebroadband.com