Spatial modulation schemes and modem architectures for millimeter wave radio systems
- Autores: Ahmed Raafat Hosny Mohamed Fahmy Raafat
- Directores de la Tesis: José Vidal Manzano (dir. tes.), Adrián Agustín de Dios (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2020
- Idioma: español
- Materias:
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- Resumen
Therapid growth of wireless industry opens the door to several use cases such as internet of thingsand device to device communications which require boosting the reliability and the spectral efficiencyof the wireless access network, while reducing the energy consumption at the terminals. The vast spectrumavailable in millimeter-wave (mmWave) frequency band is one of the most promising candidates to achievehigh speed communications. However, the propagation of the radio signals at high carrier frequenciessuffers from severe path-loss which reduces the coverage area. Fortunately, the small wavelengths of themmWave signals allow packing a large number of antennas not only at the base station (BS) but also atthe user terminal (UT). These massive antenna arrays can be exploited to attain high beamforming andcombining gains and overcome the path-loss associated with the mmWave propagation. In conventional(fully digital) multiple-input-multiple-output (MIMO) transceivers, each antenna is connected to a specificradio-frequency (RF) chain and high resolution analog-to-digital-converter. Unfortunately, these devicesare expensive and power hungry especially at mmWave frequency band and when operating in largebandwidths. Having this in mind, several MIMO transceiver architectures have been proposed with thepurpose of reducing the hardware cost and the energy consumption.
Fully connected hybrid analog and digital precoding schemes were proposed in with the aim of replacingsome of the conventional RF chains by energy efficient analog devices. These fully connected mappingrequires many analog devices that leads to non-negligible energy consumption. Partially connected hybridarchitectures have been proposed to improve the energy efficiency of the fully connected transceivers byreducing the number of analog devices. Simplifying the transceiver’s architecture to reduce the powerconsumption results in a degradation of the attained spectral efficiency.
In this PhD dissertation, we propose novel modulation schemes and massive MIMOtransceiver designto combat the challenges at the mmWave cellular systems. The structure of the doctoral manuscript canbe expressed as In Chapter 1, we introduce the transceiver design challenges at mmWave cellularcommunications.Then, we illustrate several state of the art architectures and highlight their limitations. After that, wepropose scheme that attains high energy efficiency and spectrum efficiency.
In chapter 2, first, we mathematically describe the state of the art of the SM and highlight the mainchallenges with these schemes when applied at mmWave frequency band. In order to combat thesechallenges (for example, high cost and high power consumption), we propose novel SM schemesspecifically designed for mmWave massive MIMO systems. After that, we explain how these schemescan be exploited in attaining energy efficient UT architecture. Finally, we present the channel model,systems assumptions and the transceiver devices power consumption models.
In chapter 3, we consider single user SM system. First, we propose downlink (DL) receive SM (RSM)scheme where the UT can be implemented with single or multiple radio-frequency chains and theBS can be fully digital or hybrid architecture. Moreover, we consider different precoders at the BSand propose low complexity and efficient antenna selection schemes for narrowband and widebandtransmissions. After that, we propose joint uplink-downlink SM scheme where we consider RSM inthe DL and transmit SM (TSM) in the UL based on energy efficient hybrid UT architecture.
In chapter 4, we extend the SM system to the multi-user case. Specifically, we develop joint multi-userpower allocation, user selection and antenna selection algorithms for the broadcast and the multipleaccess channels.
Chapter 5 is presented for concluding the thesis and proposing future research directions.
