Low-cost Mobile Wireless Communications
There is this NetworkWorld Article about a new way of doing XG Technology pushes new form of wireless VoIP called xMax. This product fills in the gap between WiFi, WiMAX and 3G.
The company says xMax can send a 3.7Mbps signal 18 miles with a directional antenna using 38 milliwatts and could provide phone coverage to Ft. Lauderdale, Fla., for $3.2 million in infrastructure costs vs. $299 million for 3G wireless … XG Technology’s gear operates in the unlicensed range of 902G to 928GHz.
Ok. Let us look at this a little closer.
- Versus WiFi. The xMax system has better range and coverage than WiFi. WiFi’s range is limited to a smaller area than necessary for a mobile communications system. The cell sites will have to be spaced too closely to each other. However, WiFi can potentially provide better reliability and greater bandwidth.
- Versus WiMAX. The xMax system has portability which is not available to WiMAX (at least in its current fixed wireless incarnation). WiMAX can provide a really good deal of bandwidth and range at the expense of mobility.
- Versus 3G. The xMax system is cheaper than typical 3G technologies like WCDMA and CDMA2000 radio access networks. xMax also has the benefit of using an unlicensed frequency and not needing the traditional GSM core.
Here we can see that xMax has certain advantages and disadvantages over the three (3) incumbent wireless technologies: better range versus WiFi, portability not available to WiMAX and lower cost than 3G. Another benefit is that this new system does not use traditional telephony technology such as SS7 and traditional core components. It uses newer IP-based technologies such as SIP and traditional IP routing. This is probably why the cost can potentially be very low. It has limited interoperability on traditional CMTS systems (a signaling gateway can possibly used to provide interoperability) at the expense of having greater interoperability with IP-based networks. It definitely seems like a good idea. A more mature version of the original WiFi VoIP idea.
Another possible limitation is the radio frequency being used. The 900 GHz range is getting closer and closer to the visible light spectrum (430 THz). It is still pretty far off. But as we get closer to visible light, we become more prone to interference and require line of sight. Even at the current 2.7GHz range, we are starting to get interference problems. These problems will be worst for the higher ranges such as 900 GHz. This is over and above the fact xMax is a proprietary technology.
All is not lost yet. Maybe when Mobile WiMAX comes into the market, we can revisit this idea. Imagine: WiMAX RAN and IP Core (including VoIP).
July 26th, 2006 at 10:31 am
It´s not 900 GHZ, it´s 900 MHZ.
Nice article other than that misinformation.
July 26th, 2006 at 10:36 am
Operating in the unlicensed ISM 900 MHz band, the simulation implements the critical features of the xG technology and allows users to integrate xG technology with various channel scenarios in the familiar MATLAB® environment.
here is the info from the company´s website. The article you have linked was totally incorrect in this case.
July 26th, 2006 at 10:40 pm
Aha! That is a major difference. If this system operators on the 900MHz band instead of the 900GHz band it should not be prone to line-of-sight related problems. At least, not any more than the current GSM technology that also uses the 900MHz. Of course, in some countries like the Philippines, we don’t have an ISM band in the 900MHz range. Oh well.
July 27th, 2006 at 1:44 am
[…] Network Core. In my previous discussion about the possibility of a Low-cost Mobile Communications system, it is possible to use an all IP core system with technologies such as DNS, DHCP, RADIUS/DIAMETER and others to provide some of the core services. Other services can be connected using signaling gateways and adapters to traditional systems. […]
December 3rd, 2006 at 7:23 am
[…] A few months back I wrote about some ideas on getting really low-cost mobile wireless communications services off the ground with the use of VoWiFi. In a follow-up article about IP MNOs, I mentioned three (3) important ingredients in a mobile communications network: Mobile Access Network, Network Core and Handset Support. I did mention WiFi and Mobile WiMAX as an alternatives to GSM and CDMA (and their 3G counterparts). However, at that time, WiFi did not have as much coverage as GSM or CDMA. However, with a WiFi system called roofnet, things might actually change. Roofnet is an experimental 802.11b/g mesh network in development at MIT CSAIL which provides broadband Internet access to users in Cambridge. There are currently around 20 active nodes on the network, which you can see using our real-time connectivity map. […]