Spectrum seems similar to real estate. At least that's the image that is conjured up by the often used analogy "public or private beachfront?".
You could argue the beach (spectrum) belongs to government (regulator) who should plan its best use for its people, either by selling it off (licensed spectrum) to an investor (carrier) with strict clauses for its development (cellular infrastructure coverage) and ensuing use by paying visitors (subscribers), or by keeping it a public space open and free to all (unlicensed spectrum). This seems like a pretty good analogy but it seems to ignore one key contributor that is throwing a spanner in the works: technology advancement, or more accurately, semiconductor improvements. Wireless data is exploding through the usage of new wireless handhelds and devices and there is no end in sight. The Internet-of-Things is looming, further intensifying the situation as seers predict everything with a current running through might potentially be a source of further wireless data. So all sights are set on "spectrum" to offer a cure, and governments (regulators) who ultimately own it. Indeed, we need more spectrum. And lots of it.
Spectrum is big money
Spectrum is where big money meets legislation meets high-tech, yet always bound to the perennial laws of physics. It's a billion-dollar industry that encompasses auctioning, immense investments for operators who build nation-wide networks, influenced by a constant stream of new technologies that improve connectivity for all. Proponents of the one camp (licensed) rightfully argue that the immense investments for carriers building nation-wide networks require long-term perspectives for ensuring a profitable business. The other side (unlicensed) maintain that only open policies guarantee fair and efficient use of the airwaves and lead to universal, affordable and ubiquitous broadband for all. A case of "Cellular" vs. "WiFi" is in the ring for the next round."Spectrum Crunch" - a myth?
The crux of the issue is that much of our spectrum, particularly around the "sweet spot" is already in use. At least that what the skeptics purport, creating a shortage or "spectrum crunch" myth. The truth is a little more varied and subtle though. |
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Radio spectrum extends for 3 kHz to 300 GHz and mobile phones currently operate between 700 MHz to 2.6 GHz in this range - the so-called "sweet spot" based on state-of-the-art technology. Note, that this sweet-spot spectrum block represents roughly just under 1 % of available "radio spectrum". Spectrum shortage? Well, yes, in a way, if you regard what's exploitable using today's available technology. Just as broadcast AM radio in the early decades of the last century relied on valves and tubes for frequencies up to 15 kHz, today's semiconductor technology defines wireless communications around the 1 GHz mark. But what about tomorrow?
First approach: making the best of "redundant" spectrum
To date specific blocks in the full radio spectrum range have been allocated for specific purposes or services by governments, and most of these are historical in context. For example blocks for maritime navigation, aeronautical navigation, public safety, broadcast TV etc. A true patchwork as can be seen in Sebastian Anthony's "wireless crunch" blog for ExtremeTech. Of course spectrum is a unique and therefore valuable resource, but it does differ from oil, gas, minerals etc. which face continuous depletion until none are left. Spectrum can be revitalized by closing older, inefficient services, as has or is being done for analog TV, or by making use of "white space" consisting either of unused spectrum blocks or guard bands between used blocks/frequencies that were required in prior times for broadcast and communications technology to work.Technology advancements increase spectrum usage
As the needle of technology heads towards the future, better usage in existing spectrum blocks and new usage in regions higher on the spectrum map become available accordingly. Ever decreasing semiconductor process nodes ensure the implementation of mathematical algorithms providing better modulation techniques and other advancements that ultimately increase bandwidth and bit rate per Hertz of frequency. Of course at the heart of cellular and wireless communications is the trade-off in providing the best capacity (more bandwidth/higher bit rates using higher frequencies) for the largest possible coverage area (lower frequencies are better here). Broadly speaking, lower frequencies travel further than higher ones but cannot carry as much information. The current sweet spot for wireless communications is determined by these facts and primarily governed by what's technically possible based on state-of-the-art semiconductors. Advances in semiconductor technology will allow the sweet spot to travel further up the spectrum over time and provide better bandwidth. The diagram below shows how these advancements will ultimately lead to the still amorphous 5G technology as we get closer to the year 2020 where wireless Gigabit speeds will become reality.
Does your devices' antenna size still matter?
Fitting a large antenna or satellite dish on your roof works for great TV reception, but what about handheld/portable wireless communication devices? One of the limiting factors of wireless devices has always been the required size of the antenna for transmission and reception. Antennas "resonate" at one quarter of a frequency's wavelength. Taking this factor into account for the typical current "sweet spot" frequency at 1 GHz leads to a minimum necessary antenna size of 7.5 cm which resembles an acceptable cell phone size. At 300 MHz this increases to 25 cm whereas at 3 GHz we get down to 2.5 cm. In other words, higher frequencies spell out smaller device form factors, or more room for integrating antenna arrays, read MIMO et al. As these new antenna technologies come into play, data rates can be increased through better wireless performance in several respects, irrespective of the maximum bit rate achievable by the modem dictated by modulation techniques/Shannon's theorem.Some worthwhile spectrum vs. technology resources
Spectrum, it's allocation, management and better exploitation through technology is a complex field in itself. Both free and subscription-based resources provide great insight into the issues at hand. Regarding today's 4G technology, we've reached the max in terms of squeezing as many bits as possible per Hertz of spectrum, as eloquently reported by Kevin Fitchard at Gigaom on wireless networks as workhorses of the web. A further great reference is Frank Rayal's blog looking at the capacity-coverage issue for licensed and non-licensed band. It investigates and compares differences in this respect for LTE and WiFi, both using a 20 MHz band. Certainly both camps have convincing points to advocate as we move further down the timeline. Telecoms and spectrum expert Gunjan Idrayan writes a regular insightful blog on spectrum and wireless with a particular focus on the situation in the United States and India. You'll also find some timeless articles about licensed and unlicensed spectrum as well as mobile broadband written by Peter Rysavy. Furthermore here's a short list of paid research that is well worth investigating if spectrum belongs to the core of your professional work.
The Global Spectrum Database
PolicyTracker
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Spectrum Auction Tracker
Analysys Mason
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2G, 3G, & 4G Mobile Network Subscriptions, Spectrum Licensing, Ownership, Infrastructure Contracts & Handset Shipments Database
Signals and Systems Telecom
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Spectrum for Mobile Broadband
IDATE
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Radio Spectrum Intelligence
Tolaga Research
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There are many more market research reports on the topic of spectrum available, and you can also stay on top of the latest worldwide events by signing up at wi360 (free). You will receive email alerts on new research and events regarding the specific topic of spectrum.
Spectrum's future
Governments that regulate spectrum and the technology sector that provides the devices for wireless access are both doing their best by squeezing the most out of a limited resource. Yet each of them works with a completely different heartbeat and thus the "divide" is increasing at an alarming level to the detriment of the consumer and subscriber. Wi-Fi over the past decade is a case in point how unlicensed spectrum has been addressed remarkably well at breakneck speed outside of government intervention. At the same time, network investments in the licensed spectrum must also remain a lucrative business for carriers. With the subscriber in mind, the golden age of raking in exorbitant cash amounts by governments through spectrum auctioning requires a future rethink.Our spectrum future will be mapped out how well concepts from all parties will be mutually respected and implemented.
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