1. Tx spectral masks for mixed mode (adaptive modulation)

2. ETSI standards for P-MP Current multipoint (MP) standards in Europe specified by a number of ETSI EN’s Frequency rangeAccess MethodETSI Multipoint System Equipment Standard < 1 GHzAllEN 301 460 1 – 3 GHzTDMAEN 300 636 1 – 3 GHzFDMAEN 301 373 1 – 3 GHzDS-CDMAEN 301 055 1 – 3 GHzFH-CDMAEN 301 179 3 – 11 GHzTDMAEN 301 021 3 – 11 GHzFDMAEN 301 080 3 – 11 GHzDS-CDMAEN 301 124 3 – 11 GHzDS-CD/TDMAEN 301 744 3 – 11 GHzFH-CDMAEN 301 253 24.25 – 29.5 GHzAllEN 301 213 31.0 – 33.4 GHzAllDEN/TM 4116

3. 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 3 - 11 GHz 24 - 29 GHz 31 - 33 GHz Multipart Standard 4130

4. Tx spectral masks in MP standards Masks designed according to 3 rd -order intermodulaton / net filter discrimination (NFD) for like systems operating in adjacent channels e.g. in 3 – 11 GHz band:

5. 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 ……..

6. Inconsistencies in current standards < 1 GHz 1 – 3 GHz 3 - 11 GHz 24 - 29 GHz Multipart Standard 4130 ????? } Mixed mode not applicable 1 mask Single-mode masks, but silent on mixed mode Mixed mode must use most stringent mask (except if guardband exists)

7. Different objectives for Tx spectral mask in mixed mode ManufacturersOperatorsRegulators ObjectiveWould like option of least stringent mask. Would like option of most stringent mask. Dynamically change mask to follow modulation order ? Advs.Cheaper PA, greater link budget, longer range. Less adj. channel interference -> better use of spectrum. Most accurate ? Most logical ? Disadvs.More interference within block. Higher cost terminals. Restricted range. Difficult to measure mask.

8. 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 (a)Specify least stringent mask in mixed mode, but advise that the option to use tighter mask is also provided to help operators with interference. (b)Specify default option as most stringent mask, but allow optional mode with a relaxed mask to help manufacturers meet the spec. (c)Specify that the mask must change dynamically with the modulation. (d)Allow any Tx mask to be used within the block allocation, provided that the block edge mask is not exceeded.

9. Conclusions 1.Mixed mode Inconsistencies need to be resolved in new draft standard 4130 2.Must be finalised by December 2003 to be included in 4130 3.Comments / suggestions / proposals to : Malcolm Sellars msellars@cambridgebroadband.com