What is Radio Stripe | Advantages and disadvantages of Radio Stripes
This page covers advantages and disadvantages of Radio Stripes and its basics. It mentions benefits or advantages of Radio Stripes and drawbacks or disadvantages of Radio Stripes.
What is Radio Stripe ?
Cellular network uses one APs for each of the cells allocated based on regions to be served. This leads to interference between neighbour APs. In cell free architecture, each user is served by all APs in its area of significance. Cell free architecture follows user centric design. Radio stripe consists of many antennas embedded in the cable or on adhesive tape which can easily be installed anywhere. Radio stripes are used in outdoor and indoor areas such as densely populated city squares, cultural places, malls, stadiums, train stations, busy airports, factories, warehouses etc. Refer Cell free Massive MIMO architecture in which radio stripes are used.
Figure-1, Image Courtesy : Ericsson and Linköping University Sweden
Antennas used in radio stripes are very small and hence can easily be integrated into cable or tape. Actual radio stripes may contain tape or adhesive glue on backside similar to LED stripes. For 3.5 GHz frequencies, antennas may come out of the cable slightly as shown in the figure-1. For 10 GHz and higher frequencies, they get more and more embedded inside the cable itself due to reduced sizes. As shown in the figure-1, all the antennas are arranged one after the other like daisy chain. Single CPU (Central Processing Unit) is mounted or printed at the end of the tape.
Figure-2, Image Courtesy : Ericsson and Linköping University Sweden
As shown in figure-2, two antenna elements are connected with single APU. APUs (Antenna Processing Units) are interfaced using connector to provide power and clock. Each of these APUs contain DSP (Digital Signal Processor), ADC (A to D converter), DAC (D to A converter), filters, I/Q modulators, signal amplifiers, phase shifters, attenuators as per design. All the antenna elements and APUs are enclosed using protecting material. Figure shows CPU at the end of the tape. Neighbouring CPUs are connected with each other as shown. A CPU is also called stripe station as it connects with one or more radio stripes.
For embodiments, additional sensors or actuators are added to the radio stripe which include temperature sensors, vibration sensors, miniature microphones & speakers etc.
Benefits or advantages of Radio Stripes
Following are the benefits or advantages of Radio Stripes:
➨It offers good service to users due to its availability everywhere and closer to users.
➨Cell free architecture followed by radio stripes is flexible due to its support for many use cases.
➨Radio stripes are light in weight and can be installed easily like cables, on lamp posts, on pillars etc.
➨Radio stripes are designed for scalability and reduced cost.
➨Radio stripes use very small components. Hence it is possible to manufacture them using printed electronics method which creates electronic components on various substrates.
➨Radio stripes are invisible. Hence they offer better look to surroundings unlike Base Station Antennas on tower.
➨Due to highly distributed architecture, there is limited impact to the system when one or few stripes are defected.
➨The signal transmitted from radio stripe antennas are not directional but omni-directional. Moreover it requires low power level.
Drawbacks or disadvantages of Radio Stripes
Like all the new technologies, there are few challenges or drawbacks or disadvantages of Radio Stripes.
These challenges can be overcome in future with further research in the domain.
➨Radio stripe design requires cell phone grade components.
➨Accurate synchronization and coordination among antennas and APUs is essential requirement of cell free network.
➨Wireless technology at such high frequencies (>10 GHz) is susceptible to disturbances. For example, the signal can easily be blocked by a hand.
➨Symbol level synchronization is crucial to enable joint coherent transmission. Coherent combination at receiver is required as two APs transmit to same UE simultaneously. Clustering is necessary to minimize delay and synchronization errors.