Monostatic MIMO Backscatter Communications

Capture-Aware Identification of Mobile RFID Tags With Unreliable Channels

“…According to (25), (26), and (27), the Minimum Squared Error (MSE) method can be used to estimate the number of tags, P trR , P Rrt , and α. Note that the path loss of the forward and reverse channels between two communication antennas are roughly identical [40,45,46,47]. The reasons are as follows.…”

On Energy Allocation and Data Scheduling in Backscatter Networks With Multi-Antenna Readers

“…However, finding the closed-form optimal values of f (t) and α(t) is more difficult, since they are coupled through the SINR terms of all BNs. We use the Lagrangian dual transform [53] and the quadratic transform [52] to reformulate Problem (19) and facilitate finding the closed-form optimal values of f (t) and α(t). Lagrangian dual transform, introduced in Lemma 2, converts the link scheduling problem to a problem of maximizing the sum of ratios.…”

“…in the sense that Problem (24) leads to the same solution and maximum value as Problem (19). Here, γ = (γ 1 , .…”

“…The low-energy transmission efficiency is a major problem in BCNs. However, the studies in, e.g., [8]- [19], show that exploiting multiple antennas increases the energy efficiency remarkably. Considering the energy required for channel training, [8] optimizes the transmit beamforming to maximize the harvested energy by the BNs.…”

“…Considering ambient BCNs, [12]- [17] study the beamforming optimization of a multi-antenna Reader or multi-antenna BNs. In [18] and [19], the achievable diversity order of a multiple-input-multipleoutput monostatic BCN is studied. Furthermore, optimizing the reflection coefficients of the BNs is studied in, e.g., [20]- [25], where maximizing energy efficiency, throughput or fairness in the BCNs is investigated.…”