LMDS stands for local multipoint distribution service. It is a type of high-speed wireless internet transmission which works using microwaves. At one time, it was seen as a potential solution for expanding home broadband services, particularly in the United States. Today it appears somewhat outdated and has generally been overtaken by rival technologies.
The microwaves used by the LMDS system are of a much higher frequency than radio waves. Whereas most current wireless internet services broadcast on frequencies of around 2 to 3 GHz, LMDS uses frequencies of around 26 to 31 GHz. The exact frequencies used vary from location to location and the ranges may be limited by local regulations and licensing.
The main use of LMDS is as a point-to-multipoint communications system. This means that information can be transferred from one point, the local station, to multiple users. Information transmitted back by any one user only goes back to the local station, rather than to all other users.
Because of this capability, LMDS was once championed as a possible solution for the problem of getting high speed internet access to homes. It was seen as a way of getting round the high costs of transmitting high-speed information from local telephone exchanges to homes. As LMDS can theoretically transmit large amounts of data at high speeds, it was sometimes dubbed “wireless cable” as a way to get across the concept.
There is an argument that LMDS failed to take off because of unfortunate timing. Early in the 21st century, many technology companies whose stock prices had arguably become overvalued suddenly began to get into financial difficulties. This led to a sudden lack of confidence in the industry which may have caused some firms to abandon or slow down plans to develop LMDS.
Today, there is arguably little need for LMDS. Many homes in the areas it seemed most suited for now have a fixed-line option for high-speed internet such as broadband ADSL or cable services. There are also rival systems which are faster, more reliable and have better industry support. Internet users also now have more options for receiving internet services through a cellphone connection.
LMDS does still exist in the United States and is regulated by the Federal Communications Commission. As with many FCC regulated technologies, the country is split into 493 areas known as Basic Trading Areas, each based around a major city. Within each area, two licenses are awarded for 10-year intervals through an auction system. The two licenses cover services operating at two different frequencies.