WAGreg(03)02 5 GHz WLAN Advisory Group (WAG) Regulatory Subgroup, meeting no.2 Date: Source: Contact: 8 January 2003 Broadband Wireless Association (BWA) Barry Lewis Tel: +44 1276 479087, +44 7867 523873 Fax: +44 1276 479087 Email: email@example.com Introduction Document WAGreg(02)05 provides the summary notes of the last meeting and section 3 (Draft IR) highlights the need for further discussion on the need for a channel arrangement defined in the regulatory framework. This paper provides a considered view from members of the BWA on this issue. In addition the topic of inter-operator coexistence has been identified in the summary notes and a BWA view on this topic is included here also. Channel Plans A number of BWA members agree with the views expressed at the last meeting considering that a channel plan does not require definition within the regulatory framework for FWA in the 5.8 GHz band. This is not a new approach. Recently, in order to facilitate the greatest technological flexibility, the ERC Recommendation1 developed for Fixed Service use of the 40 GHz band provides guidance on formulating assignments within the band but does not define any specific channel plan. This approach is considered appropriate to the 5.8 GHz band since: It affords the greatest flexibility to fit around existing band users. It has the potential to improve the efficiency of spectrum utilisation. It maximises FWA technological neutrality. A FWA channel plan offers no advantage regarding sharing with other non-FWA services. 1 ERC Recommendation (01)04 WAGreg(03)02 Inter-Operator Issues Licensed FWA operators have generally enjoyed “exclusive” assignments at least within the geographic boundaries of their licence and this has enabled a degree of predictability regarding the likelihood of interference from both co-frequency and adjacent frequency sources emanating from other operators in the band. The two main interference scenarios considered are co-frequency interferers in adjacent geographic areas and adjacent frequency interferers in the same geographic area. The former is usually dealt with by applying some form of regulatory emission limit at or across the licence area boundary and the latter is generally dealt with by requiring some frequency separation – guard frequency – often built into the administrative frequency planning (and sometimes combined with minimum spacing constraints between systems). Many reports have been published on these topics2. However, for the 5.8 GHz band, and in order to foster the lightest possible regulatory and administrative regime, it is understood that specific measures like boundary PSFD limits and mandated guard frequencies may not be desirable within the light licensing regime proposed. Therefore it is likely that a variety of features and characteristics will need to be inherent in the equipment and system design that will mitigate the effects of interference. For example, systems able to detect interference and then to select a different operating channel, helped by systems utilising the narrowest occupied bandwidth and therefore most able to find (either manually or automatically) a channel free from interference. But still some concerns remain regarding the potential impact of unintentional interference that in the least damaging case might only delay data throughput due to re-transmission requirements but with a worst case deployment might render a major element of any wireless network inoperable. Very often, service difficulties brought about by poor deployment are blamed on the wireless equipment itself or seen as justifying any (ill) perceived notions concerning the viability of wireless transmission itself. Therefore it is paramount that both the opportunities and risks compared to operation in licensed bands should be made very clear to parties not closely involved and familiar with the subtleties and detail of fixed wireless deployment. 2 ERC Report 99, ETSI Technical Report TR 101-853, IEEE802.16 Recommended Practice, ERC Recommendations (00)05, and (01)03.