/corporate/news/ newsreleases/2005a/03_09_05_mimo_ofdm.html) In another Nortel trial (see http://telephonyonline.com/wireless/technology/mimo_ofdm_091905/), using OFDM and MIMO enabled a mobile user to download a 264MB file at 37Mbps while simultaneously viewing two live streaming videos, over a standard 5MHz PCS band. The download took less than 1 minute in this trial; it would take 90 minutes with today's networks. OFDM and MIMO are critical technologies associated with most of the advanced and emerging wireless systems, including Beyond 3G (B3G) or 3.5G and 4G. Many areas of wireless solutions employ OFDM. One is mobile wireless, which includes the IEEE 802.16e, IEEE 802.20, and Flash-OFDM standards. Another is fixed wireless broadband, encompassing IEEE 802.16a/Revision D, WLANs such as IEEE 802.11a and 802.11g, and the European HiperLan2. OFDM is also used in Ultra-Wideband (UWB) PANs. DTV and HDTV using the Digital Video Broadcasting- Terrestrial (DVB-T) and Digital Audio Broadcasting (DAB) standards also rely on OFDM. Military high-frequency modems also make use of OFDM. OFDM is also used in a variety of wired broadband alternatives, including ADSL (where it is Spectrum Utilization known as Discrete Multitone [DMT]), cable modems, and powerline telecommu- nications (PLT). OFDM is a combination of two key principles: Multicarrier transmission-Multicarrier transmission is a technique that divides the available spectrum into many subcarriers, with the transmission rate reduced on each subcarrier. OFDM is similar to FDM in that multiple- user access is achieved by subdividing the available bandwidth into multi- ple channels that are then allocated to users. However, OFDM uses the spectrum much more efficiently than FDM by spacing the channels much more closely together. This is achieved by making all the carriers orthogo- nal (i.e., at right angles to or independent of) to one another, preventing interference between the closely spaced carriers. Making the carriers for each channel orthogonal to one another al