Receiver Architectures

Wireless Receiver Architectures Towards 5G: Where Are We?

“…3, known as the image-reject filtering [2], [6], [7], [12]. The requirements for these filters depend on the choice of IF: if the IF is high, then the wanted signal is far away from the mirror frequency [6], [7], [10], [12]. However, even when the IF is high, this results in stringent filtering requirements, so these filters cannot be integrated [6], [10].…”

“…3b. In the latter case, the signal is digitized at the IF stage (hence the name digital-IF) and the quadrature downconversion is performed in the digital domain [6], [7], [10], placing it on the intersection of the two bottomright octants of the framework, as shown in in Fig. 1 and 2.…”

“…3. Block diagram of (a) dual-conversion quadrature superheterodyne receiver (diagram based on [2], [7], [9], [10], [12], [13]) and (b) digital-IF receiver (diagram based on [1], [6], [10], [22]). Elements in the analog domain are outlined in black, while elements in the digital domain are outlined in grey.…”

“…4 and Section III-B) directly converts to baseband. The homodyne receiver is the most common architecture used in low-power applications due to its simplicity and scalability [10], and can be fully integrated [9], [23]. However, it suffers from DC-offset [1]- [7], [9], [10], [24]- [26], flicker noise [1], [3]- [5], [8], [10]- [12] and even-order intermodulation [1], [5], [11]- [13] issues.…”

“…3a and Section III-A). By choosing the IF and filters properly excellent selectivity and sensitivity can be achieved using the superheterodyne receiver [1]- [3], [9], [10], and there are no DC-offset and leakage problems [2], [9], [10]. However, the (external) high-Q (surface acoustic wave (SAW), bulk acoustic wave (BAW) or film bulk acoustic resonator (FBAR)) filters that are required for image rejection and channel selection increase the cost, size and power consumption [2], [4], [9] and limit the flexibility, which becomes even more pressing in view of the required flexibility in 5G.…”