Technical-Economic Impact of UWB Personal Area Networks on a UMTS Cell: Market-Driven Dynamic Spectrum Allocation Revisited

Recently, ultra-wide-band (UWB) technology has been approved for communication applications, utilising spectrum in use by other technologies. Recent studies have evaluated the technological impact of UWB on UMTS, but not the corresponding economic impact. This is of paramount importance, given huge investments already made on UMTS. Those studies also target "traditional" spectrum allocation. Dynamic spectrum allocation (DSA) exploits temporal/spatial variations in the "loads" of various networks. A recent proposal implements DSA by periodically selling or auctioning short-term spectrum licenses, and solves the problem of a participating CDMA cell populated by delay-tolerant terminals with dissimilar "willingness to pay" operating at various data rates, on the downlink. In the present work, UWB personal/body area networks (PAN/BAN) are introduced in the aforementioned DSA environment. The UWB networks utilise the spectrum for free, and do not compete for customers against the CDMA networks, but do increase the noise experienced by the CDMA terminals. The present work studies the economic impact of UWB on a CDMA cell, and its terminals. Before considering DSA, the techno-economic management of a CDMA cell with a fixed spectrum allocation (relevant to present day networks) is studied. The analysis reveals that neither the service priorities nor the technological operating point of the data terminals is affected by UWB. Consequently, a served terminal\´s contribution to network revenues remain unchanged. The network bears the brunt of UWB interference, because the network can fit fewer terminals in a given spectrum allocation, yet receives an unchanged amount of revenue from each served terminal.