Wireless Myths, Realities, and Futures: From 3G/4G to Optical and Quantum Wireless

• Published in: Proceedings of the IEEE 2012-05, Vol.100 (Special Centennial Issue), p.1853-1888
• Main Authors: Hanzo, Lajos, Haas, Harald, Imre, Sándor, O'Brien, Dominic, Rupp, Markus, Gyongyosi, Laszlo
• Format: Article
• Language: English
• Subjects: 3G mobile communication; 4G mobile communication; Applied sciences; Cellular capacity; Cellular networks; cellular systems; Channel estimation; channel state information (CSI); design loss; Equipments and installations; Exact sciences and technology; implementation loss; infrared communications; MIMO; Mobile radiocommunication systems; Multiaccess communication; multiple-input-multiple-output (MIMO) systems; Optical fiber communication; Optical telecommunications; optical wireless (OW); quantum communication; Radio frequency; Radiocommunications; Services and terminals of telecommunications; Shannon bound; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Telemetry. Remote supervision. Telewarning. Remote control; Throughput; Transmission and modulation (techniques and equipments); visible light communications; Wireless communication; wireless future; Wireless optical communications
• ISSN: 0018-9219; 1558-2256
• DOI: 10.1109/JPROC.2012.2189788

1) The Myth: Sixty years of research following Shannon's pioneering paper has led to telecommunications solutions operating arbitrarily close to the channel capacity-"flawless telepresence" with zero error is available to anyone, anywhere, anytime across the globe. 2)The Reality: Once we leave home or the office, even top of the range iPhones and tablet computers fail to maintain "flawless telepresence" quality. They also fail to approach the theoretical performance predictions. The 1000-fold throughput increase of the best third- generation (3G) phones over second-generation (2G) GSM phones and the 1000-fold increased teletraffic predictions of the next decade require substantial further bandwidth expansion toward ever increasing carrier frequencies, expanding beyond the radiofrequency (RF) band to optical frequencies, where substantial bandwidths are available. 3) The Future: However, optical and quantum-domain wireless communications is less developed than RF wireless. It is also widely recognized that the pathloss of RF wireless systems monotonically increases with the carrier frequency and this additional challenge has to be tackled by appropriate countermeasures in future research. Hence, we set out to seek promising techniques of tackling the aforementioned challenges and for resolving the conflicting design constraints imposed on the flawless telepresence systems of the future. To disspell the myth, we evaluate both the operational 3G as well as the emerging fourth-generation (4G) wireless systems and demonstrate that there is a substantial difference between their theoretical and their practically attainable performance. The reality is that the teletraffic predictions indicate further thirst for bandwidth, which cannot be readily satisfied within the most popular 1-2-GHz carrier-frequency range, where the best propagation conditions prevail. We briefly consider the 10-300-GHz unlicensed band as a potential source of further spectrum, followed by a review of advances way beyond the upper edge of the RF range at 300 GHz, namely to the realms of optical wireless (OW) communications. As the carrier frequency is increased, the pathloss is also increased, which results in ever smaller cells. Furthermore, the high-frequency RF waves predominantly obey line-of-sight (LOS) propagation-like visible light. The future requires advances in both infrared and visible-light communications for circumventing the LOS nature of light. We hypothesize that light-emitti