Claudio Armani - Academia.edu (original) (raw)
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Graduate Center of the City University of New York
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Papers by Claudio Armani
IEEE International Conference on Communications, 2003. ICC '03.
ABSTRACT This paper presents a new uplink beamforming technique applied to the WCDMA system, here... more ABSTRACT This paper presents a new uplink beamforming technique applied to the WCDMA system, here called partial-adaptive beamforming. Instead of concentrating upon the performance of every single user, the radiation pattern aims to maximize the performance of a group of users and only a limited number of beams has to be formed. We present two algorithms that group effectively the users (grouping algorithm) and shape the radiation pattern (shaping algorithm) in order to enhance the performance of all users being part of the same group. The required hardware and the computational complexity of the proposed algorithms compared to the fully-adaptive beamforming technique is drastically reduced. Simulation results show a considerable gain respect to the fixed beam approach in terms of increased capacity and enlarged coverage. Furthermore the algorithms converge at a speed suitable to implement them following the dynamic evolution of the traffic within the sector.
Journal of Signal Processing Systems, 2016
Journal of Signal Processing Systems, 2013
ABSTRACT Future digital air/ground communication systems (LDACS) will operate on the L-Band where... more ABSTRACT Future digital air/ground communication systems (LDACS) will operate on the L-Band where the coexistence with existing legacy systems shall be guaranteed. This paper proposes a scheme to detect and mitigate the JTIDS impulsive interference on LDACS-1 system. The novel idea advised here is the transmission of two copies of the symbols received with interference that are suitably combined at the receiver after a blanking operation of the corrupted samples. In particular two alternatives are presented that differ for the adopted retransmission policy, namely \textit{full combining} scheme, where all the symbols are transmitted twice, and \textit{partial combining} scheme, which foresees the retransmission of only those symbols where interference has been detected. Both these methods permit to efficiently remove the interference without affecting the useful information and exploiting profitably the diversity gain against noise through the soft combining approach. The numerical results provided in the paper highlight a good behavior of the proposed methods and significant advantages in comparison with the traditional blanking method, either in terms of Bit Error Rate and Throughput.
IEEE Transactions on Vehicular Technology, 2003
This paper deals with a multiuser cancellation-detection scheme combined with antenna array for w... more This paper deals with a multiuser cancellation-detection scheme combined with antenna array for wideband code-division multiple-access (WCDMA) communication systems in which different traffic loads and data rates are considered. This receiver, defined as space-time selective parallel interference-cancellation detector, should be used at the base station of a WCDMA communication system. Asynchronous users and multipath fading phenomena are considered in our analysis. The receiver basic assumption is to divide signals into two different groups according to the received power level. The reliable signals are directly detected and cancelled from the whole received signal at each sensor before making the decision about unreliable signals without any further processing delay. Performance evaluations have been carried out in terms of P (bit error probability) by means of computer simulations. In particular, it is shown that the receiver described in this paper exhibits good behavior and lowers the computational complexity in comparison with previously proposed alternatives. Index Terms-Antenna array, code division multiple access (CDMA), universal mobile telecommunication systems (UMTS).
IEEE Transactions on Vehicular Technology, 2009
This paper deals with a cognitive approach able to guarantee the coexistence of new data link for... more This paper deals with a cognitive approach able to guarantee the coexistence of new data link for air-ground aeronautical communications LDACS and military JTIDS systems. Future LDACS shall coexist with current systems operating in the same frequency band for this reason coexistence issues must be carefully investigated. In particular JTIDS transmissions can affect the LDACS performance acting as disruptive impulse noise. JTIDS exploits frequency hopping to protect information, hence its interference on LDACS system cannot be foreseen and avoided. In addition the bandwidth of the two signals results to be completely overlapped in case of collision. The disruptive effects of JTIDS interference on LDACS can be mitigated if the collisions can be detected and hence suitable processing techniques can be activated. This paper proposes a method to detect the presence of JTIDS interference exploiting an energy detection spectrum sensing technique based on sliding windows and packets retransmission. The performance of the proposed method is presented in terms of missed detection probability of the JTIDS interference and error rate of the LDACS system showing a significant capability to counteract JTIDS interference.
IEE Seminar MIMO: Communications Systems from Concept to Implementation, 2001
IEEE International Conference on Communications, 2003. ICC '03.
ABSTRACT This paper presents a new uplink beamforming technique applied to the WCDMA system, here... more ABSTRACT This paper presents a new uplink beamforming technique applied to the WCDMA system, here called partial-adaptive beamforming. Instead of concentrating upon the performance of every single user, the radiation pattern aims to maximize the performance of a group of users and only a limited number of beams has to be formed. We present two algorithms that group effectively the users (grouping algorithm) and shape the radiation pattern (shaping algorithm) in order to enhance the performance of all users being part of the same group. The required hardware and the computational complexity of the proposed algorithms compared to the fully-adaptive beamforming technique is drastically reduced. Simulation results show a considerable gain respect to the fixed beam approach in terms of increased capacity and enlarged coverage. Furthermore the algorithms converge at a speed suitable to implement them following the dynamic evolution of the traffic within the sector.
Journal of Signal Processing Systems, 2016
Journal of Signal Processing Systems, 2013
ABSTRACT Future digital air/ground communication systems (LDACS) will operate on the L-Band where... more ABSTRACT Future digital air/ground communication systems (LDACS) will operate on the L-Band where the coexistence with existing legacy systems shall be guaranteed. This paper proposes a scheme to detect and mitigate the JTIDS impulsive interference on LDACS-1 system. The novel idea advised here is the transmission of two copies of the symbols received with interference that are suitably combined at the receiver after a blanking operation of the corrupted samples. In particular two alternatives are presented that differ for the adopted retransmission policy, namely \textit{full combining} scheme, where all the symbols are transmitted twice, and \textit{partial combining} scheme, which foresees the retransmission of only those symbols where interference has been detected. Both these methods permit to efficiently remove the interference without affecting the useful information and exploiting profitably the diversity gain against noise through the soft combining approach. The numerical results provided in the paper highlight a good behavior of the proposed methods and significant advantages in comparison with the traditional blanking method, either in terms of Bit Error Rate and Throughput.
IEEE Transactions on Vehicular Technology, 2003
This paper deals with a multiuser cancellation-detection scheme combined with antenna array for w... more This paper deals with a multiuser cancellation-detection scheme combined with antenna array for wideband code-division multiple-access (WCDMA) communication systems in which different traffic loads and data rates are considered. This receiver, defined as space-time selective parallel interference-cancellation detector, should be used at the base station of a WCDMA communication system. Asynchronous users and multipath fading phenomena are considered in our analysis. The receiver basic assumption is to divide signals into two different groups according to the received power level. The reliable signals are directly detected and cancelled from the whole received signal at each sensor before making the decision about unreliable signals without any further processing delay. Performance evaluations have been carried out in terms of P (bit error probability) by means of computer simulations. In particular, it is shown that the receiver described in this paper exhibits good behavior and lowers the computational complexity in comparison with previously proposed alternatives. Index Terms-Antenna array, code division multiple access (CDMA), universal mobile telecommunication systems (UMTS).
IEEE Transactions on Vehicular Technology, 2009
This paper deals with a cognitive approach able to guarantee the coexistence of new data link for... more This paper deals with a cognitive approach able to guarantee the coexistence of new data link for air-ground aeronautical communications LDACS and military JTIDS systems. Future LDACS shall coexist with current systems operating in the same frequency band for this reason coexistence issues must be carefully investigated. In particular JTIDS transmissions can affect the LDACS performance acting as disruptive impulse noise. JTIDS exploits frequency hopping to protect information, hence its interference on LDACS system cannot be foreseen and avoided. In addition the bandwidth of the two signals results to be completely overlapped in case of collision. The disruptive effects of JTIDS interference on LDACS can be mitigated if the collisions can be detected and hence suitable processing techniques can be activated. This paper proposes a method to detect the presence of JTIDS interference exploiting an energy detection spectrum sensing technique based on sliding windows and packets retransmission. The performance of the proposed method is presented in terms of missed detection probability of the JTIDS interference and error rate of the LDACS system showing a significant capability to counteract JTIDS interference.
IEE Seminar MIMO: Communications Systems from Concept to Implementation, 2001