IST-2003-507581 WINNER D2.5 v1.0 Duplex ... - Celtic-Plus

WINNER D2.5 v1.0The baseline noise power appearing in the output of (analog) receiver, expressed as equivalentinput noise in the antenna. The output interface is typically placed at the input of the analog-todigitalconverters. The noise floor consists of thermal noise from the radio channel, and of noiseoriginating in the receiver itself, the latter quantity being commonly expressed through the noisefigure of the receiver.Receiver selectivityThe capability of the receiver to suppress unwanted interference components appearing outsidethe wanted frequency channel. Selectivity consists of the combined effect of the analog anddigital filters in the system. It is also affected by the analog-to-digital converter sampling rate.Receiver linearityAll analog signal processing is to some extent nonlinear. Non-linearity gives a rise to signaldistortion via crossmodulation and intermodulation, and limits the capability of the receiver toresolve weak input signals when strong interference occurs in the other channel/channels.Receivers typically need to be quasi-linear over the dynamic range of interest, such that a thirdorderTaylor series expansion is sufficient to characterise the non-linearity. The second and thirdorder non-linearities are commonly expressed through respective input intercept points (IIP).Adjacent channel power (ACP)Unwanted signal power integrated over the adjacent channel. Receivers are usually mostsensitive to interference in the first adjacent channel. This is because channel filters usually havenot reached their maximum suppression at the corner of the adjacent channel, and because of thespectral regrowth of the interference signal to the wanted channel due to non-linearity.Transmitter adjacent channel power ratio (ACPR)To achieve high efficiency, it is beneficial to operate transmitters and, in particular, poweramplifiers as close to saturation as feasible. As a consequence of the resulting strong nonlinearity,the transmitted signal experiences spectral regrowth and power leaks to the adjacentchannels. ACPR is defined as the ratio of the unwanted power in the adjacent channel to thetransmitted signal power in the wanted channel. Because the power transmitted to adjacentchannels appears directly as interference to users in those channels, ACPR must be strictlycontrolled by specifying spectrum masks.Transmitter noise floorWideband noise floor generated by the transmitter. Noise originates in Tx chain, and the poweramplifier amplifies it. Typically the out-of-band noise floor is filtered out with a RF filter afterthe PA. In full duplex FDD it is important to have low noise floor since the noise at RX bandwill deteriorate the sensitivity of the receiver. To allow simultaneous operation of different radiosystems in the same geographical area at different frequencies, the noise floors of each systemmust be strictly regulated via spectrum masks.Page 102 (121)