The Myth: Sixty years of research following Shannon’s pioneering paper has led to telecommunications solutions operating arbitrarily close to the channel capacity - ’flawless tele-presence’ with zero error is available to anyone, anywhere, anytime across the globe...
The Reality: The popularity of smart phones and tablet-computers has led to tele-traffic congestions in public places having a high user-density, hence failing to support ’flawless tele-presence’ quality, as seen in Figure 1.
Figure 1. People form communities of interest for disseminating the IoCI.
The Future: Hence Beam-Me-Up has expanded the horizon of classic Radio-Frequency (RF) systems to the hitherto rarely used 30 - 60 GHz mm-wave spectral bands and to optical wireless frequency bands, where plenty of bandwidth is available for circumventing the looming spectrum-crunch. Our predicament is however that as the carrier frequency is increased, its wavelength is reduced and hence rain-drops, vegetation and other factors attenuate the signal more severly, as seen in Figure 2. Hence Beam-Me-Up conceived sophisticated, high-gain beamforming solutions for counteracting this increased attenuation. As for indoor optical wireless communications, Beam-Me-Up designed sophisticated solutions based on the Light-Emitting Diode (LED) based downlink transmitters relying on the state-of-the-art LED-bulbs exemplified in Figure 3. The corresponding system is seen in Figure 4. These solutions may be expected to find their way into next-generations Beam-Me-Up-style tele-presence systems.
Figure 2. Pathloss versus carrier frequency, portraying the typical oxygen and water vapour absorption phenomena [Steele & Hanzo, 1999].
Following half-a-century of Moore’s law, the advances in semi-conductor technology are portrayed in the stylized illustration of Figure 5. contemporary semi-conductor technology is approaching nanoscale integration and the ’traveller’ enters the world of quantum physics, where many of the physical phenomena are rather different from those of classical physics. A feasible design option is to simply make the chip-area larger in an attempt to accommodate more sophisticated signal processing on a single chip, but without more dense integration. However, this option has many disadvantages, above all that the ’yield of fault-free chips’ is dramatically reduced.
Hence Beam-Me-Up opted for the more radical option of contributing to making quantum communications an engineering reality by exploring the elements of the ’quantum jig-saw puzzle’, with special emphasis on the following elements:
Given the vulnerable nature of quantum circuits, the tiniest of environmental interference perturbs their quantum state, which is hence collapsed back into the classic world and all benefits of parallel processing in the quantum domain evaporate. Beam-Me-Up conceived near-optimal quantum error corrections codes for correcting both the bit-flips and phase-flips inflicted by the quantum decoherence phenomenon, which are portrayed in Figure 6. At the current state-of-the-art these codes are vital for extending the coherence interval of all quantum circuits and computers.
Figure 6. Quantum Forward Error Correction (QFEC) codes support reliable quantum computing and communication
systems by mitigating the bit-flips and phase-flips imposed by quantum decoherence.
The second line of research contributed to making the perfectly secure ubiquitous quantum Internet a reality, which requires numerous radically new components, such as quantum-repeaters and quantum-key-distribution (QKD) solutions, which also require quantum-memory. Chinese scientists established quantum entanglement distribution over a record-distance of 1200 km, hence QKD may be deemed to be the most mature quantum technology, which is closest to commercial reality. Beam-Me-Up contributed a suite of new network-coded QKD solutions, as well as to the conception of large-scale repeater networks with the aid of quantum-network-coding and entanglement swapping investigations.
Beam-Me-Up also exploited the formidable computing power of quantum-search algorithms (QSAs) - conceived by the computer-science-oriented quantum community - for solving numerous largescale search problems found in wireless communications. This future-proof research simulated a future quantum-computer by a classic parallel computer. For example, large-scale multi-user detection problems were solved at the base-station (BS), where all K users supported in the mobile-to-BS uplink were simultaneously detected by using as few as square-root K cost-function evaluations. This search problem becomes extremely challenging for a large number of users, especially, when the system relies on high-throughput multi-level modulation schemes, as required by today’s systems. An even more grave challenge is, when the BSs are interlinked by optical fibre and after exchanging their received information make a joint decision about all the users’ information in all cells, as illustrated in Figure 7.
Further cutting-edge solutions were conceived for other large-scale search problems, such as joint data and channel estimation and for transmit preprocessing in support of multi-user transmission, where the knowledge of the downlink channel is exploited for eliminating the potential inter-user interference that would be encountered in the hostile dispersive downlink channel. As a benefit, the mobile user would receive clean, flawless signal and hence low-complexity single-user reception can be invoked.
Finally, Beam-Me-Up also designed new QSAs for futuristic localization-aided wireless services. Additionally, these QSAs were used for solving large-scale routing problems, such as those involved in Aeronautical Ad Hoc Networks.
Figure 7. Large-Scale ulti-User/ulti-Cell Detections in Cooperative Multi-cell Processing.
