DAS (Distributed Antenna Systems) have come under a lot of criticism from the small cell community in the past, being positioned as expensive, difficult and time-consuming to install. We thought it time for a DAS vendor to put their side of the story, and spoke with Tony Lefebvre, Director Product Management at TE Connectivity, to highlight the tradeoffs.We concluded that both DAS and Small Cells are needed to meet future needs, with different scenarios where each could be more suited.Comparing the fundamental architecture and components.In both cases, cellular signals are transmitted from multiple RF radio heads spread around high traffic areas. DAS systems comprise relatively dumb radio units connected usually by dedicated fibre cables to a central machine room/hosting location, equipped with racks of traditional macrocell basestations. The baseband processing happens in the basestations, allowing additional capacity to be installed at the central location. DAS systems can be shared by multiple operators, each connecting their own basestations to the shared RF distribution system. Multiple radio heads can simulcast the same RF signal, allowing the same capacity to be delivered over multiple floors of a building or campus areas. Wideband designs allow each DAS radio head to transmit across all licenced bands and for multiple operators simultaneously. Small cells are designed with full basestation capabilities and processing onboard, reducing the requirements for backhaul to IP broadband, usually over Ethernet. They implicitly provide additional capacity through frequency reuse, with each unit providing an additional sector. Small cells are usually single operator and single frequency band today, although multi-band/multi-technology products are becoming available.
via WiFiNovation | Scoop.it
Aucun commentaire:
Enregistrer un commentaire