Design of a Configurable Complex IF Receiver Supporting LTE Carrier Aggregation

An RF Receiver for Intra-Band Carrier Aggregation

“…1(c), another user's strong signal may act as part of the image and fold onto channel 1 or 2 after downconversion. The image problem is addressed in [4]- [7] in the analog domain. Depicted in simplified form in Fig.…”

“…As illustrated in Fig. 7(c), we multiply by in the frequency domain, 7 obtaining a signal that upon combining with Q, cancels the images.…”

“…From the foregoing observations and noting that in Fig. 15 is equal to , we can express the downconverted LNA noise appearing in as (7) which, from (4), reduces to (8) The baseband noise of is downconverted in the same manner: (9) where . We must now calculate the noise contributed by the TIA.…”

“…We use the notations A and B to refer to both the RF channels and the IF channels 7. Frequency-domain multiplication is denoted by a cross in a square to avoid confusion with time-domain multiplication.…”

Using Analog Complex Mixers for Low-IF Mixing

“…Image rejection is known to be sensitive to mismatches in the receiver path. IQ mixer has been thoroughly analysed in [1], the same architecture for carrier aggregation is proposed in [10], and for simultaneous multi-carrier reception in [11]. Complex IF Receiver in [10] relies largely on calibrating the IQ stage, which may be difficult in sub-THz receivers.…”