A lot has been made of the coming introduction of 3G, a network that will provide broadband-like speeds to mobile phones. The introduction of the service will, if the pundits are to be believed, creat
A lot has been made of the coming introduction of 3G, a network that will provide broadband-like speeds to mobile phones. The introduction of the service will, if the pundits are to be believed, create a revolution for the mobile phone industry. The speeds afforded by 3G will enable applications not before dreamt of in the mobile realm - videoconferencing, streaming media, high-speed Internet access to name a few.
The 3G services - which should be available from all the major mobile phone carriers - will provide users with speeds up to 2Mb/s. The rate will vary depending on the location of the target device and the speed at which it is moving. The latter occurs because of a trade-off between signal robustness and bandwidth. A target moving at walking speed will be limited to about 384Kb/s, while one in a moving car will only be able to get around 144Kb/s.
Services are available in few places around the world. In Australia, 3G was expected to be introduced this year, although recent reports indicated that buyers will have to wait until the end of next year before services become available. For the moment, they will have to use standard GSM (at 9.6Kb/s) or General Packet Radio Services (GPRS, sometimes called 2.5G, running at 56Kb/s to 114Kb/s). Looking abroad, Japans NTT DoCoMo recently rolled out 3G services, with handsets priced at the equivalent of about $1,600.
In Australia, the recent introduction of GPRS does not point to a consumer-friendly introduction for 3G. The carriers charge for it by the kilobyte, making it a very expensive application. Telstra, for instance, charges 2.2c/Kb.
Its also likely that the cost of handsets for 3G will be very high. Prices are expected to start at the $3,000 mark - a lot of money for something you carry around in your pocket. Still, hopes are high that in the long term, as costs drop, 3G will be a technology that everybody will have access to, and one that will fundamentally change the way we communicate when on the move.
3G is not the only wireless technology with a big future. Wi-Fi, also known as IEEE 802.11b, is a wireless Ethernet standard that can deliver 11Mb/s to devices within a range of about 100m. Originally developed as a wireless LAN standard, some of the more recent applications for 802.11b are proving very interesting. In several locations in the US, groups have set up communal Internet connection shares through 802.11b. For instance, one person can set up a connection sharing gateway to a broadband connection using a PC with both standard Ethernet (to connect to the cable or ADSL modem) and Wi-Fi cards. Everybody within range can use the gateway via 802.11b, effectively providing a large group of people (an apartment block or building, for instance) with very cheap Internet access. The cost of the one broadband connection, spread across a large group of people, would be very small indeed.
Wavelength division multiplexing
A lot is made of the speed at which processor speeds and storage capacity have increased in the past 20 years. Heres news: compared to the speed at which optical networking has improved, processors and hard disks look downright tardy. The amount of data that can be carried over optical fibre has increased by a factor of three or more per year over the past five years. The most important ingredient in this evolution has been the introduction of wavelength division multiplexing (WDM), a technology that will save us from the bandwidth blues.
WDM will be primarily used by telecommunications carriers to drastically increase the amount of bandwidth available on their networks (including the Internet). Its also possible that it will be used for LANs and direct-to-home applications such as consumer broadband, although this is not likely for a very long time.
It sounds complicated, but the principle behind WDM is very simple: use different wavelengths of light (that is, colours) to carry data in parallel over fibre-optic cabling.
A typical optical cable can technically handle bandwidth of 25,000GHz, but todays electronics can only deliver a few gigahertz of modulated information at best, limiting the maximum speed achievable over optical fibre to a few gigabits per second. WDM overcomes this limitation, however, allowing multiple electronic devices to multiplex the data over the cable (using the different wavelengths) and come closer to the theoretical capacity of the cable. The amount of data carried by each wavelength varies depending on the modulation system used, but can be anywhere up to several gigabits per wavelength. Multiply this rate by the number of wavelengths used in a transmission, and you can get some seriously fast data transfers.
WDM had conceptual roots in 1995, and although practical products exist today that can multiplex 32 or more streams, most researchers believe that the technology has a long way to go. Indeed, not long after its introduction, researchers showed off what they called dense wavelength division multiplexing (DWDM), which could carry upwards of one terabit per second of information on 160 streams across a single cable.
Now researchers are talking about ultra-dense WDM, supporting up to 400 wavelengths. In laboratories, engineers at Lucent have showcased optical fibres running 1,000 wavelengths, and many believe 15,000 or more wavelengths on a single fibre strand is possible. That would be enough to carry the worlds entire Internet traffic on one cable!
Researchers are also talking about using WDM for routing purposes, with each logical connection represented by a different wavelength. This frees a network from electronic transactions (where the wavelength is demodulated, processed, routed and then re-modulated) and allows data to flow straight on through to the destination. Theoretically, this can reduce latency and increase speed dramatically, although this technique has yet to be applied in the field.
So what has this somewhat esoteric technology have to do with you? Hopefully, the explosion of WDM will mean that bandwidth becomes so abundant that its not even worth measuring. Until that day, we can look forward to more broadband for more people.