 be regarded as being competitively unfair. This increase in tension can be ascribed to a number of factors. Additional bands are being allocated with terms and obligations that differ from previous allocations. Each additional band introduces additional insertion loss and reduced isolation through the switch paths and filters in user equipment. This will result in unforeseen and unexpected interference issues but also reduces spectral efficiency. Multiple technologies are being introduced into legacy bandwidth with minimal consider- ation as to the likely impact on proximate bandwidth and other user communities. This will result in unforeseen and unexpected interference issues, but also reduces spectral efficiency. Existing bands are being extended to accommodate these multiple technologies. The 10- MHz extension to the 850 band in the US is an example. This will result in unforeseen and unexpected interference issues but also reduces spectral efficiency. Channel bonding is being introduced to meet an assumed market demand for peak data rates of up to 1 Gbps. This will result in unforeseen and unexpected interference issues but also reduces spectral efficiency. MIMO is being introduced in parallel with channel bonding on similar assumptions. MIMO may result in unforeseen and unexpected interference issues and will certainly reduce average throughput rates, effectively a reduction in system efficiency. Operational requirements are being imposed on operators without due consideration of the spectral implications. Mandatory E911 support for example fails to take into account that the second harmonic of 787.5 MHz, between C band and D band mobile transmit in the US 700 MHz band falls directly on the GPS receive frequency in L band at 1575 MHz. Terrestrial use of L band may also compromise GPS front-end receiver performance, a problem that Light Squared had to contend with through 2011. All of the above increase performance uncertainty both in terms of band-to-band perfor- mance, within-band channel-to-channel perfor