In-Band Full-Duplex Wireless: Challenges and Opportunities

Sabharwal, Ashutosh; Schniter, Philip; Guo, Dongning; Bliss, Daniel W.; Rangarajan, Sampath; Wichman, Risto

doi:10.1109/jsac.2014.2330193

Cited by 1,907 publications

(1,140 citation statements)

References 121 publications

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“…In formulating the problem, we make the following assumptions: (i) the transmitter is aware of its own signal, i.e., x a is known at node a, which is a commonly adopted assumption in the literature [3,5], (ii) the interference channel h aa and the communication channel h ba are unknown deterministic parameters, (iii) the transmit symbol from node b is modeled using a discrete random distribution, and (iv) we observe N independent received symbols. The blind channel estimation problem requires the knowledge of the joint probability density function (PDF) of all observations, which is derived from the conditional PDF of a single observation.…”

Section: Problem Formulationmentioning

confidence: 99%

“…We can see that as the SI power increases, the BER performance of the proposed technique remains nearly constant. This is because in FD communication the self-interference signal is completely known to the receiver [3]. Consequently, for relatively small channel estimation error of the proposed estimator, the SI can be cancelled regardless of its power.…”

Section: Effect Of Power Of Si Signalmentioning

confidence: 99%

“…1 Note that the system model for FD communication in (1) is applicable to per subcarrier communication in orthogonal frequency division multiplexing (OFDM) FD communication [3,5,41]. 2 Note that it may be possible to achieve constellation asymmetry through other means, such as design of irregular modulation constellations.…”

Section: Endnotesmentioning

confidence: 99%

See 2 more Smart Citations

Superimposed signaling inspired channel estimation in full-duplex systems

Koohian

Mehrpouyan

Nasir

et al. 2018

EURASIP J. Adv. Signal Process.

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Residual self-interference (SI) cancellation in the digital baseband is an important problem in full-duplex (FD) communication systems. In this paper, we propose a new technique for estimating the SI and communication channels in a FD communication system, which is inspired from superimposed signaling. In our proposed technique, we add a constant real number to each constellation point of a conventional modulation constellation to yield asymmetric shifted modulation constellations with respect to the origin. We show mathematically that such constellations can be used for bandwidth efficient channel estimation without ambiguity. We propose an expectation maximization (EM) estimator for use with the asymmetric shifted modulation constellations. We derive a closed-form lower bound for the mean square error (MSE) of the channel estimation error, which allows us to find the minimum shift energy needed for accurate channel estimation in a given FD communication system. The simulation results show that the proposed technique outperforms the data-aided channel estimation method, under the condition that the pilots use the same extra energy as the shift, both in terms of MSE of channel estimation error and bit error rate. The proposed technique is also robust to an increasing power of the SI signal.

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Section: Problem Formulationmentioning

confidence: 99%

Section: Effect Of Power Of Si Signalmentioning

confidence: 99%

See 1 more Smart Citation

Superimposed signaling inspired channel estimation in full-duplex systems

Koohian

Mehrpouyan

Nasir

et al. 2018

EURASIP J. Adv. Signal Process.

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show abstract

“…Avoiding the issue of the transmitting signal interfering with the receiving signal requires operation at either different times or at different frequencies. However, prospects for creating an in-band full-duplex system, which would allow for transmitting and receiving on the same frequency at the same time, have shown that full-duplex is feasible [1][2][3][4][5][6]. Ideally, this would allow twice as many devices to make use of a given spectrum at any time.…”

Section: Introductionmentioning

confidence: 99%

Compact Antennas With Reduced Self Interference for Simultaneous Transmit and Receive

Makar¹,

Kim²,

Tran³

et al. 2017

PIER C

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Abstract-A microstrip antenna system operating in the 2.4 GHz WLAN band is presented for in-band full-duplex operation. The design includes a patch antenna fed by a 180 • hybrid. Two feeding methods are presented, probe and aperture. The measured bandwidths are 2.5% (60 MHz) and 2.1% (50 MHz) for the probe fed and aperture fed, respectively. The probe fed system reaches measured isolation (S 21 ) < −50 dB and the aperture fed < −45 dB in a reflective environment. The design also has low cross polarization, reasonable gain values, and a very low envelope correlation coefficient (< 0.01).

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“…Sabharwal et al discussed two methods of interfacing antennas to an IBFD wireless system: (i) separate-antenna FD and (ii) shared-antenna FD [1]. In the shared-antenna model, a bidirection circulator is used to transmit and receive signals without modifying many architecture standards, thus the RF hardwares such as antenna, RF cable and filters can be saved [2].…”

mentioning

confidence: 99%

Self-interference suppression with imperfect channel estimation in a shared-antenna full-duplex massive MU-MIMO system

Xing

Liu

Zhai

et al. 2017

J Wireless Com Network

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In this paper, we consider a shared-antenna full-duplex massive MU-MIMO system and prove that the self-interference (SI) at the base station (BS) can be suppressed, though the direct-path SI exists and the signal/SI channel is imperfectly estimated. The BS is assumed to employ zero-forcing (ZF) or maximal-ratio transmission/maximal-ratio combining (MRT/MRC) method to linearly process signals. We propose a precoded SI channel training scheme by employing orthogonal sequences and downlink precoding, so the SI channel can be estimated like the signal channel with a much lower dimension. Based on the channel estimation, we further analyze the SI suppression by combining the SI removal and the large-scale antenna linear processing (LALP) method. Numerical results show that an additional 36 dB SI can be suppressed by combining the SI removal and the LALP suppression. We derive the tight closed-form lower bounds of the achievable rates for the combined suppression. Finally, we maximize the system spectral efficiency and energy efficiency based on the simulation and closed-form approximations.

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In-Band Full-Duplex Wireless: Challenges and Opportunities

Cited by 1,907 publications

References 121 publications

Superimposed signaling inspired channel estimation in full-duplex systems

Superimposed signaling inspired channel estimation in full-duplex systems

Compact Antennas With Reduced Self Interference for Simultaneous Transmit and Receive

Self-interference suppression with imperfect channel estimation in a shared-antenna full-duplex massive MU-MIMO system

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