Multi-Carrier Index Keying for Next Generation Gigabit Wireless Communications
Lead Research Organisation:
Queen's University Belfast
Department Name: Sch of Electronics, Elec Eng & Comp Sci
Abstract
An exponential increase in mobile data traffic has been observed in the last decades. This will continue and a 1000-fold increase by 2020 has been forecasted. Future wireless communications promise to provide the required data rate by an utilisation of the increasing spectrum.
Multicarrier Modulation (MCM) techniques have found application in the majority of modern wireless communication systems, due to strong inherent immunity to multipath fading, which allows for a significant increase in the data rate. MCM effectively transforms a frequency selective fading channel into parallel flat fading channels which immensely simplifies the data recovery process at the receiver. However, these benefits come at the cost of a loss of energy efficiency due to the distribution of finite power to multicarrier signals, an increased sensitivity to frequency offset and Doppler shift as well as transmission nonlinearity caused by the non-constant power ratio of MCM signals. Such drawbacks of MCM challenges its direct application to 5G systems that request a 1000-fold increase in the data rate (e.g., 100 gigabits per second), compared to 4G system that has its ideal peak rate of 100 megabits per second.
Additionally, the limited power availability at the mobile client coupled with these transmission rate demands present challenges which can be solved by increasing bandwidth over shorter ranges; about 250 times larger than today 4G is considered in 5G. Due to the time-varying nature of wireless channels, training sequences need to be transmitted periodically for the purpose of channel estimation. The overload imposed by training sequences for channel estimation of such a large bandwidth can be significant, especially for power-limited device applications. Power-limited transmission and large spectrum modulation challenges must be simultaneously tackled.
This project introduces a simple and low-cost mapping method for index keying based multicarrier systems in dispersive channels. The key concept involves a special index mapping function named MCIK (multicarrier index keying). At every transmission, only a few random sub-carriers are active for high energy-efficiency and, simultaneously, index of the active/inactive sub-carriers helps inherently to transmit extra information bits with no extra power. This MCIK concept is promising to effectively transmit big data volumes at low-power, especially on the large bandwidth and realistic dispersive channels. Our goal is to provide theoretical references and guidelines for a successful MCIK implementation that can produce significant advance; our preliminary results show 50% power savings and a potential rate of tens of gigabits per second over classical multicarrier transmission. MCIK is suitable for a power limited system modulating a large number of multicarrier. It provides a mechanism for attaining both diversity and multiplexing so that the energy efficiency and the spectral efficiency are increased. We also propose to design a linearly processed MCIK system to facilitate a low-cost data recovery process, resulting in higher spectral efficient multicarrier system. In order to effectively overcome carrier frequency offset and multiuser interference problems in the current orthogonal frequency division multiple access (OFDMA) transmissions, we propose a new multiple access technique which can allow the practical performance limits and needs for the desired performance to be easily obtained and show how MCIK features should be combined with multiuser multiple-input multiple-output systems.
Our emphasis in this work will be on the study of special properties of 'index keying' process in MCIK which have been overlooked by others. We aim to leverage these properties in the context of multicarrier index modulation, detection and estimation, and multiple access design. This is to attain optimal performance with affordable computational complexity, for future wireless communications.
Multicarrier Modulation (MCM) techniques have found application in the majority of modern wireless communication systems, due to strong inherent immunity to multipath fading, which allows for a significant increase in the data rate. MCM effectively transforms a frequency selective fading channel into parallel flat fading channels which immensely simplifies the data recovery process at the receiver. However, these benefits come at the cost of a loss of energy efficiency due to the distribution of finite power to multicarrier signals, an increased sensitivity to frequency offset and Doppler shift as well as transmission nonlinearity caused by the non-constant power ratio of MCM signals. Such drawbacks of MCM challenges its direct application to 5G systems that request a 1000-fold increase in the data rate (e.g., 100 gigabits per second), compared to 4G system that has its ideal peak rate of 100 megabits per second.
Additionally, the limited power availability at the mobile client coupled with these transmission rate demands present challenges which can be solved by increasing bandwidth over shorter ranges; about 250 times larger than today 4G is considered in 5G. Due to the time-varying nature of wireless channels, training sequences need to be transmitted periodically for the purpose of channel estimation. The overload imposed by training sequences for channel estimation of such a large bandwidth can be significant, especially for power-limited device applications. Power-limited transmission and large spectrum modulation challenges must be simultaneously tackled.
This project introduces a simple and low-cost mapping method for index keying based multicarrier systems in dispersive channels. The key concept involves a special index mapping function named MCIK (multicarrier index keying). At every transmission, only a few random sub-carriers are active for high energy-efficiency and, simultaneously, index of the active/inactive sub-carriers helps inherently to transmit extra information bits with no extra power. This MCIK concept is promising to effectively transmit big data volumes at low-power, especially on the large bandwidth and realistic dispersive channels. Our goal is to provide theoretical references and guidelines for a successful MCIK implementation that can produce significant advance; our preliminary results show 50% power savings and a potential rate of tens of gigabits per second over classical multicarrier transmission. MCIK is suitable for a power limited system modulating a large number of multicarrier. It provides a mechanism for attaining both diversity and multiplexing so that the energy efficiency and the spectral efficiency are increased. We also propose to design a linearly processed MCIK system to facilitate a low-cost data recovery process, resulting in higher spectral efficient multicarrier system. In order to effectively overcome carrier frequency offset and multiuser interference problems in the current orthogonal frequency division multiple access (OFDMA) transmissions, we propose a new multiple access technique which can allow the practical performance limits and needs for the desired performance to be easily obtained and show how MCIK features should be combined with multiuser multiple-input multiple-output systems.
Our emphasis in this work will be on the study of special properties of 'index keying' process in MCIK which have been overlooked by others. We aim to leverage these properties in the context of multicarrier index modulation, detection and estimation, and multiple access design. This is to attain optimal performance with affordable computational complexity, for future wireless communications.
Planned Impact
What benefits will result from this research?
The ability to implement highly efficient wireless communications algorithms on a MCIK-based broadband structure will be attained. This changes how system designers implement 5G and smart city applications. The proposed research will enable smart device communications to be undertaken at source devices distributed throughout a city and thus a range of sensors, cameras, and other devices in everyday life can be connected to remotely transmit very large information on traffic, parking, security, air quality, and more. This research will change the wireless urban life by altering the dynamics of how wireless systems are developed.
What are the Economic Benefits of this research?
The target area for this research is to create an air interface solution that can be used in the smart cities, 5G systems, and wearable technology markets. These markets have considerable commercial opportunity. For example, the global smart cities market is envisaged to grow from $654.57 billion (2014) to $1,266.58 billion (2019) with a clear need to provide advanced solutions for smart homes, smart transportation, and smart security. These solutions are implemented to create a better connectivity to the data on real-time basis for efficient management and overcome difficulties of the non-regulated expansion of urban wireless hotspot areas. A new generation of 5G mobile standards may be introduced approximately in the early 2020s, promising better connections to cope with the ever-increasing number of mobile internet users as well as the expected boom in connected devices as part of the so-called internet of things over the coming years. In 2013, the EU said it would spend 700M Euro (£560 M) on 5G technology research over the next seven years (2020), while companies in the telecoms sector would provide more 3 billion Euro. The market for wearable, wireless devices that is growing from 14 million (2012) to 171 million (2016) is driven by the demand for real-time data, including personal health information. This market is expected to exceed minimum revenues of $6 billion in 2016. In the future, wireless wearable devices will not be focused only on a few products mainly for healthcare and wellness applications, but also devices for personal entertainment and military use. The applicant have a proven track record in developing a range of wireless solutions and the engagement with Samsung will ensure a direct/indirect path to commercialisation.
What are the skilled/trained people benefits of this research?
The researchers on this project will gain from a highly commercial emphasis at the ECIT and the University to develop a well-balanced technical expertise in close collaboration with the industry. The opportunity to engage directly with Samsung engineers will expose the project's researchers to world-leading wireless communications expertise.
The ability to implement highly efficient wireless communications algorithms on a MCIK-based broadband structure will be attained. This changes how system designers implement 5G and smart city applications. The proposed research will enable smart device communications to be undertaken at source devices distributed throughout a city and thus a range of sensors, cameras, and other devices in everyday life can be connected to remotely transmit very large information on traffic, parking, security, air quality, and more. This research will change the wireless urban life by altering the dynamics of how wireless systems are developed.
What are the Economic Benefits of this research?
The target area for this research is to create an air interface solution that can be used in the smart cities, 5G systems, and wearable technology markets. These markets have considerable commercial opportunity. For example, the global smart cities market is envisaged to grow from $654.57 billion (2014) to $1,266.58 billion (2019) with a clear need to provide advanced solutions for smart homes, smart transportation, and smart security. These solutions are implemented to create a better connectivity to the data on real-time basis for efficient management and overcome difficulties of the non-regulated expansion of urban wireless hotspot areas. A new generation of 5G mobile standards may be introduced approximately in the early 2020s, promising better connections to cope with the ever-increasing number of mobile internet users as well as the expected boom in connected devices as part of the so-called internet of things over the coming years. In 2013, the EU said it would spend 700M Euro (£560 M) on 5G technology research over the next seven years (2020), while companies in the telecoms sector would provide more 3 billion Euro. The market for wearable, wireless devices that is growing from 14 million (2012) to 171 million (2016) is driven by the demand for real-time data, including personal health information. This market is expected to exceed minimum revenues of $6 billion in 2016. In the future, wireless wearable devices will not be focused only on a few products mainly for healthcare and wellness applications, but also devices for personal entertainment and military use. The applicant have a proven track record in developing a range of wireless solutions and the engagement with Samsung will ensure a direct/indirect path to commercialisation.
What are the skilled/trained people benefits of this research?
The researchers on this project will gain from a highly commercial emphasis at the ECIT and the University to develop a well-balanced technical expertise in close collaboration with the industry. The opportunity to engage directly with Samsung engineers will expose the project's researchers to world-leading wireless communications expertise.
People |
ORCID iD |
| Youngwook Ko (Principal Investigator) |
Publications
Chatziantoniou E
(2016)
Performance Analysis of a Low-Complexity Detector for MCIK-OFDM Over TWDP Fading
in IEEE Communications Letters
Chatziantoniou E
(2016)
A low complexity detector with MRC diversity reception for MCIK-OFDM
Crawford J
(2017)
On the SEP Analysis of OFDM Index Modulation With Hybrid Low Complexity Greedy Detection and Diversity Reception
in IEEE Transactions on Vehicular Technology
Ko Y
(2016)
Multi-device selection scheduling in non-identically distributed fading channels
in IET Communications
| Description | New multi-carrier modulation alternative, named multi-carrier index keying OFDM, has been developed along with a low-complexity detector for a proposed scheme. The developed MCIK-OFDM concept has been further investigated to improve the energy efficiency at low complexity, which is highly desired to machine type device communications, significantly decreasing the complexity, cost, and power consumption. Especially in a massive scale of machine type device deployment, the MCIK concept ensures to exploit a subset of sub-carriers and their indices to create OFDM signals so that the potential interference levels can be properly decreased. For this, error propagation and symbol error probability performance of the designed scheme have been theoretically analysed and new results have been published at three major IEEE international conferences and in IEEE international journal. |
| Exploitation Route | A new MCIK scheme has been developed and it has been generalised to employ at various pragmatic wireless fading environments. The generalised MCIK scheme has been further investigated towards applications of massive machine type communications, 5G and Internet-of-Things, incorporating multiple antenna techniques. Accordingly, the theoretical limits of the proposed MCIK will provide a new insight on the performance of machine type communications that could work even in confined spaces (e.g., vehicle, robot) at very limited resources. Such findings will be useful to the design of various IoT connectivity applications. Based on the above, a new technique of spread index modulation has been very recently developed to enhance the transmit diversity in the classical OFDM structure. This will be useful for reliability-sensitive IoT applications that typically involve simple and inexpensive sensors. |
| Sectors | Digital/Communication/Information Technologies (including Software),Energy,Healthcare,Security and Diplomacy,Transport |
| Description | The developed concept of Index Modulation is a new modulation method for the 5G wireless networks. The OFDM Index Modulation and its variants have been providing attractive advantages over the classical OFDM that is adopted in part of many current wireless standards. |
| Sector | Digital/Communication/Information Technologies (including Software) |
| Description | Samsung visit |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Industry/Business |
| Results and Impact | 2 senior directors of Samsung R&D visited to the research organisation, which established a new strong collaboration link. |
| Year(s) Of Engagement Activity | 2016 |
| Description | School Visit (GIST) |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Around 10 postgraduate research students and academic staffs from an international institute attended to the research seminar, which sparked questions and discussion afterwards, and the school showed interest in related subject areas and collaboration opportunity. |
| Year(s) Of Engagement Activity | 2016 |