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• UMTS – the “Universal Mobile Telecom Standard” isn’t the all universal solution• Even if there would be an universal standard it would not necessarily be the
single dominating standard
• To have a standard, open and flexible architecture for a wide range of communication products - life cycle cost reductions.
• Enhanced wireless roaming by extending the capabilities of current and emerging commercial air-interface standards.
• Over-the-air download of new features and services as well as S/W patches.
• Joint Tactical Radio – DoD initiative:Unified communication across commercial, civil, federal and military organizations.
• The RF Block: “Software Defined RF”• From antenna to digital interface (OBSAI & CPRI)• Analog & digital signal processing• Frequency specific components
• The BaseBand Block: “Software Defined BB”• From digital interface (OBSAI, CPRI) to digital interface (transport)• Pure digital signal processing• Frequency independent
• The Transport Block: “End to end service”• Cellular specific networks (E1/T1 transmission, RNC, …)• IP networks
The SDR for commercial and consumer radio networks• Cellular industry: Growing number of incompatible radio technologies
Call for “technology agnostic” spectrum allocation• Consumer industry: Growing number of different applications. From low
rate RFID to high speed WLAN
• Fundamental difference between wide area and local area systems:
Wide Area• Spectral efficiency and cell planning• Coordinated spectrum usage
(minimize interference by design)• High performance RF
(TX power, RX sensitivity & blocking)Is SDR and cognitive radio feasible?
Local Area• No cell planning• Uncoordinated spectrum usage• Short term spectrum allocation• BTS (WLAN) listens before transmit• Low performance TRXSDR and cognitive radio essential
• There is no “tolerable” interference level!• Low interference affects the BTS similar like increased noise• Every minute amount of interference reduces the capacity of a
system. The effect might be tolerable in the beginning, but increases gradually with usage of the interfering system
• Gradually decreasing capacity is difficult to detect • Will be compensated with TX power and/or additional sites• Increases gradually both CAPEX and OPEX• With fatal effects on the competitiveness of the network
• “Radiotelegraphy”: Transmission of news by radiation of electromagnetic waves. • C = W log2(1 + S/N) (Shannon) E = mc2 (Einstein)
• Software• Immaterial ware, non-apparative (m=0) functional parts of an installation.
• The downlink power (PA) is shared between the users • GSM: # of timeslots per carrier, # of carriers per TRX• WCDMA: Service (BW) used by each user, noise (interference, network load)
• Cell breathing is a SDR feature!
0%
20%
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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Traffic load factor
Relative cell size
Increased load 800 kbps⇒ Decreased coverage
Low load 200 kbps⇒ Large coverage
128 kbps
64 kbps
8 kbps
128 kbps
64 kbps
8 kbps 144 kbps64 kbps
64 kbps
144 kbps
144 kbps
64 kbps64 kbps
144 kbps64 kbps
64 kbps
144 kbps
144 kbps
64 kbps64 kbps
• Traffic load has direct effect on the cell size
• Radio Resource Management provides means to control cell breathing in network optimisation