… asks Moray Rumney, Lead Technologist over at Agilent in the latest edition of the Agilent Measurement Journal (3/2007). In his article, Moray takes a look at which factors contribute to the ever increasing wireless transmission speeds and explains where the limits are and why the 300+ MBit/s promised by LTE and other technologies in a 20MHz channel will remain a theoretical promise rather then becoming a practical reality. He then goes on to describe what is possible with the given physical limits and presents his thoughts about how to address capacity issues in the future. An absolute must read!
The journal is available here and the article can be found on page 32.
4 thoughts on “What next for mobile telephony?”
Agree with you Martin, this is an absolute must read. the quality of the arguments are a pleasure to read compared to common reading on wide audience news website…
Do not let yourself be blinded by marketing arguments !! Achieving high peak datarate is nice, but the real criteria should remain average datarate.
There is an important error in the article. Geometry factor is defined as G = Ior/Ioc, not G = Ior/(Ioc+Ior). Otherwise, G would never be larger than 0 dB and all the following reasoning would be impossible. Otherwise, I agree with you that is a very interesting article, thanks for pointing to it.
Touché Ignacio! Don’t know how that one got through the proof stage. The geometry factor is Îor/Ioc. I was trying to explain the denominator as the sum of the “adjacent cell Îor” and broadband noise “Ioc” but forgot to rename the Îor. However, all the figures and reasoning that follow are correct, just the formula is wrong.
From the Agilent “What Next for Mobile Telephony?” paper:
“Pinpointing the origins of
higher data rates:
If we take a closer look at the evolution of data rates and spectral efficiency for each system, we discover six technical factors that explain the growth:
• Allocating more time (TDMA duty cycle)
• Allocating more bandwidth
• Improving frequency reuse
• Reducing channel coding protection
• Using higher order modulation
• Taking advantage of spatial diversity (MIMO) ”
A ‘totally obvious’ but potentially game changing additional factor is the (network) ‘architectural domain’: reducing cell sizes through the use of integrated SDWN approaches increases bandwidth greatly. It is conventionally understood that his comes at a cost in access rights, number of units provisioned, deployed etc. But the field has advanced to the point that self-configuration, built-in active field measurement and adaptation of relay hop and back haul is feasible. This is greatly helped by lower cost/higher performance and multi-signal chain and multi-radio IC and processor capabilities.
Improvements have been made in reduced latencies and MESH and tiered hop signaling overheads. While there remain constraints and trade-offs, the advantages of more granular adaptively scalable, and self back-hauling network topologies are significant.
This is not to say SDWN would always be the most appropriate solution, although some advocates envision wireless deployments with no macro scale base stations except ‘virtual macro cell’ aggregates of small base stations arranged to fit available/opportunistic or best business case back haul and site availability.
These enabling developments in wireless bring up the next question: “Enabling of What?”
The sift is to new MIMO/AAS-OFDM based systems that will inspire greater use of granular, smarter network topologies to deliver bandwidths and reduce costs. But what operator business and deployment models are most effective?
Unfortunately, there are several types of service, scale and density, collaborative models, topographies, and other factors that differentiate best solutions for a given operator business case. Ugh.. I should stop here.
Some course break downs are incumbent mobile and green field operators. Rural and urban. And open IP access and walled garden, prescribed service.
The dynamics of adoption can be energized beyond how the networks can be made to work to how they can be deployed to take advantage of different marketplace dynamics. Simply: how much user participation/degree of freedom is there in how the wireless network is deployed? Wi-Fi is somewhat crude and unmanaged but has taken advantage of local ownership and viral adoption by individuals and organizations to proliferate rapidly and at relative low cost/bandwidth.
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