Amitava Ghosh

Bio: Amitava Ghosh is an academic researcher from Nokia. The author has contributed to research in topics: Telecommunications link & Base station. The author has an hindex of 35, co-authored 103 publications receiving 5760 citations. Previous affiliations of Amitava Ghosh include Motorola & Motorola Solutions.

Method and apparatus for choosing a modulation and coding rate in a multi-user, mimo communication system

Abstract: A method and apparatus for choosing a modulation and coding rate in a MU-MIMO communication system is provided herein. During operation, a node will determine the MCR to feed back to the base even though the mobile does not know which of the possible interferers (if any) will be using the same time/frequency resources as the mobile. This takes place via the mobile node calculating best antenna weights (codebook choice) for each group of subcarriers that can be potentially used by the mobile. Transmit weights v for each interferer are then determined and the weights are utilized to determine a best modulation and coding rate for the mobile.

Streaming Video Capacity Comparisons of Multi-Antenna LTE Systems

Abstract: The 3GPP Long Term Evolution (LTE) Release-8 specifications are designed to deliver higher peak data rates, higher throughput and lower air-interface latency compared to 2G and 3G systems. This higher performance will make it possible to support more demanding applications beyond web-browsing and voice, requiring higher data rates and stricter QoS constraints. Video services are becoming increasingly popular over the Internet indicating that the demand for such high data-rate video applications over cellular wireless will continue to grow. However, in order to make these services commercially viable in a LTE system it is necessary for the air-interface to deliver high quality services to a significant number of users simultaneously. In this paper we investigate the video capacity of a LTE air-interface using realistic video traffic models. An LTE air-interface can support multiple-antenna transmit arrays and several multiple antenna transmission modes to increase system capacity. We investigate the benefits of using 4 transmit antennas compared to 2 transmit antennas on the video capacity of an LTE system. The results from our investigation indicate that the capacity benefits with 4 transmit antennas are much higher with video services than those observed with other traffic models such as the full-buffer traffic model. The results also show that a 10MHz TDD LTE system can service upto 48 users per sector with 256Kbps video streams in the downlink indicating that such services can be commercially viable.

Method and apparatus for implied resource assignment for uplink acknowledgment signalling

Abstract: A network node constructs ( 22 ) a downlink transmission using at least one group of resource elements. A remote unit receives ( 12 ) the downlink transmission and determines ( 13 ) a lowest index of the at least one group of resource elements. The remote unit then determines ( 14 ) an uplink resource, for use in uplink (UL) acknowledgment signaling, using the lowest index. The network node then receives ( 23, 24 ) the UL acknowledgment signaling that corresponds to the downlink transmission, the UL acknowledgment signaling having been transmitted using the uplink resource based on the lowest index. To determine the uplink resource, both the remote unit and the network node implicitly use the lowest index of the at least one group of resource elements that were used to construct the downlink transmission. Implicitly determining the uplink resource in this manner, serves to reduce overhead related to acknowledgment signaling.

Broadcast Control Strategies for mmWave Massive MIMO Leveraging Orthogonal Basis Functions

Abstract: Millimeter wave (mmWave) frequencies are being considered for future generation cellular systems because of the large amount of available spectrum in those bands (e.g., 10 GHz in the E-band alone). Additionally large scale antenna arrays with high gain adaptive beamforming are viewed as critical for overcoming the poor path loss conditions in the mmWave bands. User-specific beamforming can solve the coverage problem for user-specific data and control traffic, but the coverage problem for transmitting broadcast control information must also be solved. This paper explores the problem of enhancing the performance of a broadcast control channel, where control information must be transmitted to the entire sector in a non-user specific or multicast fashion. We propose a technique for transmitting broadcast control information in a mmWave system with RF beamforming that offers improved performance and several key advantages over a grid-of-beams type of approach where control information is simply repeated in time across successive narrow RF beams.

Coverage and rate trends in moderate and high bandwidth 5G networks

Abstract: Higher frequency bands (>6 GHz) look promising to meet the proposed 5G data rates, given the large amount of available spectrum in these bands. However, a rigorous understanding of some fundamental tradeoffs like network densification, sectorization, and bandwidths has only begun to be investigated at millimeter wave (mmW) bands. In this work, we investigate the coverage and rate performance of cellular networks with sectorized access points (APs) operating at high frequency bands, using tools of stochastic geometry. We observe that sectorizing the APs can significantly improve the data rates and thus can be used in conjunction with network densification, in order to achieve the 5G data rate requirements. However, the increased data rates come at the expense of increased interference in the network. We investigate the interference effects on a typical moderate (200 MHz) bandwidth network at 28 GHz and a high (2 GHz) bandwidth network at 72 GHz carrier frequency, with 4 sector APs and validate the trends observed with the help of detailed system-level simulations using METIS-like scenarios.

What Will 5G Be

Abstract: What will 5G be? What it will not be is an incremental advance on 4G. The previous four generations of cellular technology have each been a major paradigm shift that has broken backward compatibility. Indeed, 5G will need to be a paradigm shift that includes very high carrier frequencies with massive bandwidths, extreme base station and device densities, and unprecedented numbers of antennas. However, unlike the previous four generations, it will also be highly integrative: tying any new 5G air interface and spectrum together with LTE and WiFi to provide universal high-rate coverage and a seamless user experience. To support this, the core network will also have to reach unprecedented levels of flexibility and intelligence, spectrum regulation will need to be rethought and improved, and energy and cost efficiencies will become even more critical considerations. This paper discusses all of these topics, identifying key challenges for future research and preliminary 5G standardization activities, while providing a comprehensive overview of the current literature, and in particular of the papers appearing in this special issue.

Internet of Things: A Survey on Enabling Technologies, Protocols, and Applications

Abstract: This paper provides an overview of the Internet of Things (IoT) with emphasis on enabling technologies, protocols, and application issues. The IoT is enabled by the latest developments in RFID, smart sensors, communication technologies, and Internet protocols. The basic premise is to have smart sensors collaborate directly without human involvement to deliver a new class of applications. The current revolution in Internet, mobile, and machine-to-machine (M2M) technologies can be seen as the first phase of the IoT. In the coming years, the IoT is expected to bridge diverse technologies to enable new applications by connecting physical objects together in support of intelligent decision making. This paper starts by providing a horizontal overview of the IoT. Then, we give an overview of some technical details that pertain to the IoT enabling technologies, protocols, and applications. Compared to other survey papers in the field, our objective is to provide a more thorough summary of the most relevant protocols and application issues to enable researchers and application developers to get up to speed quickly on how the different protocols fit together to deliver desired functionalities without having to go through RFCs and the standards specifications. We also provide an overview of some of the key IoT challenges presented in the recent literature and provide a summary of related research work. Moreover, we explore the relation between the IoT and other emerging technologies including big data analytics and cloud and fog computing. We also present the need for better horizontal integration among IoT services. Finally, we present detailed service use-cases to illustrate how the different protocols presented in the paper fit together to deliver desired IoT services.

Spatially Sparse Precoding in Millimeter Wave MIMO Systems

Abstract: Millimeter wave (mmWave) signals experience orders-of-magnitude more pathloss than the microwave signals currently used in most wireless applications and all cellular systems. MmWave systems must therefore leverage large antenna arrays, made possible by the decrease in wavelength, to combat pathloss with beamforming gain. Beamforming with multiple data streams, known as precoding, can be used to further improve mmWave spectral efficiency. Both beamforming and precoding are done digitally at baseband in traditional multi-antenna systems. The high cost and power consumption of mixed-signal devices in mmWave systems, however, make analog processing in the RF domain more attractive. This hardware limitation restricts the feasible set of precoders and combiners that can be applied by practical mmWave transceivers. In this paper, we consider transmit precoding and receiver combining in mmWave systems with large antenna arrays. We exploit the spatial structure of mmWave channels to formulate the precoding/combining problem as a sparse reconstruction problem. Using the principle of basis pursuit, we develop algorithms that accurately approximate optimal unconstrained precoders and combiners such that they can be implemented in low-cost RF hardware. We present numerical results on the performance of the proposed algorithms and show that they allow mmWave systems to approach their unconstrained performance limits, even when transceiver hardware constraints are considered.

Next Generation 5G Wireless Networks: A Comprehensive Survey

Abstract: The vision of next generation 5G wireless communications lies in providing very high data rates (typically of Gbps order), extremely low latency, manifold increase in base station capacity, and significant improvement in users’ perceived quality of service (QoS), compared to current 4G LTE networks. Ever increasing proliferation of smart devices, introduction of new emerging multimedia applications, together with an exponential rise in wireless data (multimedia) demand and usage is already creating a significant burden on existing cellular networks. 5G wireless systems, with improved data rates, capacity, latency, and QoS are expected to be the panacea of most of the current cellular networks’ problems. In this survey, we make an exhaustive review of wireless evolution toward 5G networks. We first discuss the new architectural changes associated with the radio access network (RAN) design, including air interfaces, smart antennas, cloud and heterogeneous RAN. Subsequently, we make an in-depth survey of underlying novel mm-wave physical layer technologies, encompassing new channel model estimation, directional antenna design, beamforming algorithms, and massive MIMO technologies. Next, the details of MAC layer protocols and multiplexing schemes needed to efficiently support this new physical layer are discussed. We also look into the killer applications, considered as the major driving force behind 5G. In order to understand the improved user experience, we provide highlights of new QoS, QoE, and SON features associated with the 5G evolution. For alleviating the increased network energy consumption and operating expenditure, we make a detail review on energy awareness and cost efficiency. As understanding the current status of 5G implementation is important for its eventual commercialization, we also discuss relevant field trials, drive tests, and simulation experiments. Finally, we point out major existing research issues and identify possible future research directions.