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5G Wireless Networks: Potential Business Opportunities, Radio Frequency Radiation Health Issue and Capacity Expansion Challenges

babak vosooghzadeh (Oct 2017)

Introduction In order to meet the wireless capacity requirement of approximately 10 Gbits/sec per wireless device in real time, the year 2020 is set as the target for the partial deployment of 5G Wireless Networks [1] [2]. The 4G LTE-A Release 10 data rate capacity is 3Gbits / sec in real time. There are business opportunities for the deployment of the 5G Systems and in other areas due to the increase in wireless capacity. In order to meet the high capacity requirement, mm (Millimeter) Wave frequency bands (30 to 300 GHz) will be used as an option in 5G Networks and Wireless Sets. However due to high propagation loss of mm Waves [3] [4], the coverage distance is much lower with respect to the current cellular wireless networks. Therefore, Microcells with short distance Wireless Access Points will have to be employed besides the traditional (4G Legacy) Macrocells in order to relay the 5G Wireless Set mm-Wave signals to the final Mobile Gateway. This final Gateway is linked to the IP Core Network. The mentioned heterogeneous Network (HetNets) [5] is a practical method for handling the wireless traffic in 5G. The coverage distance may be increased by smart antenna beam-forming, by employing MIMO (Multiple Input Multiple Output) Base Station sectorized antennas, and by considering Printed antenna array technology such as microstrip patch or SIW (Substrate Integrated Waveguide) [6] and nano-wire based SIWs [7]. Increasing the 5G Wireless Set radio frequency power level might seem to be an option for increasing the coverage distance, but there is a constraint on the net radio frequency power emission (from Wireless Sets) near living tissues due to the maximum allowable absorption of electromagnetic energy by the living body. The 5G Wireless System devices (as radio frequency power emitters) are required to comply with electromagnetic radiation exposure guidelines before they are introduced to the consumer market [8-10]. The 5G System radio frequency spectrum (3 to 300 GHz) radiation is non-ionizing and the main safety concern is the heating (for example of the eyes, head and skin) caused by the absorption of electromagnetic energy in the living body. The peak value for the exposure metric SAR (Specific Absorption Rate) is 1.6 Watts / kg for the human head and neck region. The final Wireless Access Point (for example a Base Station) to Mobile Gateway in 5G [11] will only have the appropriate Antennas along with RRH (Remote Radio Head) portion of the RAN (Radio Access Network). The computations for the remaining RAN Base Band data processing Layers such as major portion of L1 and all portions of L2, L3 and X2 Sync (Physical, Media Access Control, Packet Data Convergence Protocol, Internet Protocol layers) will be performed away from the RRH and beyond the Mobile Gateway tie-in point. The Base Band data of various final Wireless access points will be collected in a virtual BBU (Base Band Unit) pool and Cloud (C-RAN) computations will be performed for efficient and fast access to the IP Core Network. Macrocells including traditional Base Stations are fixed entities. However, Microcells and Wireless Access Points are flexible smaller Units and they may be removed or reallocated in the G5 framework. Therefore, the Microcells and Wireless Access Points are cognitive wireless network nodes with Spectrum Sensing capabilities in order to assign available frequency bands for relaying modulated wireless signals [12]. A total of 13 GHz bandwidth is available in the 70 / 80 GHz E-band spectrum for relaying the 5G modulated signals and ultimately performing high data rate wireless backhaul by multi-channel Aggregation methods [13].

Business Opportunities Some of the business opportunities are listed below: 1- 5G Cellular Mobile Phones, 5G Modems, 5G Antennas, Internet of Things (IoT), Internet of Vehicles (IoV), Device to Device (D2D) Communication, E-healthcare, Machine to Machine (M2M) communication, Financial Technology (FinTech), Remote Medical Diagnostics, Radio Frequency Identification (RFID), Internet of Nano-Things (IoNT), Biosensors, Health Monitoring Sensors, Molecular Sensors and other Nano-Sensors There will be a big market for the mentioned Sensors or Systems, and the sensors are linked to the 5G System via wireless modules, optical / Terahertz converters and other interfaces. The 5G equipment should have remote software configuration and update capabilities. Terahertz converters are required in IoNT applications. For the IoNT, Surface Plasmon Polariton waves in the range of 0.1 to 10 terahertz frequency range can be formed on the surface of 1 micrometer x 100 nanometer wide graphene antennas to be integrated into biological and chemical nano-sensors for advanced health monitoring [14].

2- Expansion of Software Capabilities, Cloud Memory and Cloud Computations for On-Line Applications Due to the 5G data capacity, there will be more demand for Cloud Memory and On-Line software and computing Applications. 3- Enhanced Production, Design, Marketing, Advertisement, Employment Strategies and Multi-Media Processing Due to the 5G data capacity, it is possible to provide creative Interactive Video Processing applications for Marketing, Advertisement and Employment purposes. 4- Expansions in IP Core Networks, C-RAN (Cloud - Radio Access Network) Computing Modules, Aggregation Networks, Fiber Optics including Fiber to Home [15] Networks, Waveguide and Wired Networks There will be expansions in IP Core modules such as SGW (Serving Gateway), PGW (Packet Data Gateway), and MME (Mobility Management Entity). Also, the C-RAN modules are a new challenge for Software computing. The Fiber Optic Networks and other non wireless Networks are critical for easier access to Mobile Gateway and IP Core Network. However, there might be a delay for the deployment of Fiber Optic portion of 5G System due to cost feasibility studies and land access issues. The Wireless Access Nodes (which are compact small modules) can be used as a temporary (micro-cell) setup for relaying the wireless information from the end user to the IP Core Network until the Fiber Optic set up is complete. After establishing the Fiber Optic link, the removed portion of Wireless Access Nodes can be used elsewhere in the 5G System. However, Wireless Access Nodes can be used permanently (if desired) for locations that will not use non-wireless (such as Fiber Optic) Networks.

5- Wireless Access Nodes These compact modules have Cognitive Radio capabilities in order to detect free radio spectrum, and they should be remotely configured and updated. During uplink, these nodes receive modulated signals from wireless nodes (that are closer to the end user), perform modulated signal carrier aggregation and relay the result to the wireless nodes (that are closer to the IP Gateway). During downlink, the reverse operation is performed. IP Gateways are usually located near the 4G (Legacy) base station or Non-wired Network tie-in points.

These modules can be removed easily from a microcell setup when coverage distance is increased due to the advancements in signal detection technologies, or when wireless relaying is not required (usually at the microcells that are closer to the IP Gateways) at some stage due to the deployment of non-wired Networks such as Fiber Optics for easier access to IP Gateway.

Radio Frequency Radiation Health Issue The Radio frequency electromagnetic wave fields emitted from wireless sets penetrate the exposed living tissue and produce heat. The thermal effect can damage biological tissues, particularly in the head and the brain region, if the SAR (Specific Absorption Rate) level (near living tissue) does not surpass a threshold. SAR is the metric that is used to assess exposure to radio frequency electromagnetic waves, which is the rate at which the radio frequency energy is absorbed per time by a particular mass of tissue. The SAR is directly proportional to the wireless set radio frequency power level. The current safe limit set by ICNIRP (International Commission on Non-Ionizing Radiation Protection) and similar institutions in each country is SAR of 1.6 to 2 watts per kg averaged over one gram of living tissue. Also, the current ICNIRP basic restriction on net electromagnetic power density is 10 Watts per meter squared for the general public in the frequency range of 10 to 300 GHz. The SAR and power density thresholds place a constraint on the net radio frequency power (from Wireless Sets) near living tissues. However, the effect of mentioned radiation should also be investigated on all biological entities. The maximum distance between wireless nodes can be calculated by assuming that one wireless node emits its maximum allowable radio frequency power and the other node is receiving the signal near the (MDS) Minimum Detectable Signal level (which is above the noise floor power level by a few factors). Also, the available maximum antenna gain is used in the analysis of the distance along with the applicable LOS (Line of Sight) or NLOS (Non Line of Sight) electromagnetic wave propagation path loss. The maximum distance between wireless nodes can be increased by improving the wireless node antenna gain, and by employing other options that are mentioned in the Introduction. However, aside from the antenna issue, signal & wave processing options such as Stochastic Resonance [16, 17] and Nano-Waveguide [18-21] Pre-amplifier methods are under investigation to boost the desired sub-threshold signal between the antenna and the wireless set front end (primary) amplifier. In our context, sub-threshold signal is defined as the signal with average power level below the sensitivity (MDS level) of the wireless node primary amplifier. In Stochastic Resonance option which is dependent on the modulation scheme, the auxiliary signal is adaptively injected between the antenna and the primary amplifier in order to recover and retain major portions of the subthreshold signal. By a using a non-linear stochastic process after the primary amplifier along with a stochastic resonance quality measure, the auxiliary signal along with the stochastic process parameters are adaptively updated and the desired signal is retrieved by conventional baseband channel and signal decoding schemes. In the Nano-Waveguide approach, the electromagnetic wave (containing the desired sub-threshold signal) is confined in narrow channels between the antenna and the primary amplifier, and the kinetic energy is transferred to the sub-threshold signal waves from a DC supply or harvested energy according to Space Charge wave propagation theory,

Conclusion It is evident that the 5G Wireless System is implementable without any major technical hold point. The business opportunities for the implementation of 5G System depend on the finalization of standards for the applicable portions of the 5G System. However, the business opportunities due to the increase in data capacity such as enhanced production, marketing, advertising and employment strategies can be currently explored, since they are not depend on the 5G standards. Due to technological advancements, the coverage distance for Wireless Access Nodes will eventually increase, leading to the decrease of microcells in certain areas. Also, the microcell reduction can be due to the deployment of non-wireless (such as Fiber Optic) access points to the IP Core Gateway. In both cases, the microcells can be easily rearranged and the extra Wireless Access Nodes can be used elsewhere.

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