Headend
Equipment or facility that receives, stores, and processes television signals for distribution to a local region. The headend may control interactive features, manage VoD, and insert advertisements.

HD
High definition.

HDR
Hardware-defined radio.

HDTV
High-definition television.
A new format for television that offers far superior quality to current NTSC, PAL or SECAM systems. The resolution of the picture is roughly double previous television signals and the pictures are displayed with a screen ratio of 16:9 as compared with most of today’s TV screens, which have a screen ratio of 4:3.

HFC
Hybrid fibre/coaxial.
A telecommunication industry term for a network that incorporates both optical fibre along with coaxial cable to create a broadband network.

HFC
Hybrid fibre copper.
A broadband network that utilizes fibre optic cabling to the vicinity and then copper lines to individual users.

Hotspot
An access point to a wireless local area network (WLAN). Hotspots are areas where wireless data can be sent and received, and Internet access is provided to wireless devices. For ex-ample, a laptop computer can be used to access the Internet in a hotspot provided in an airport or hotel.

HSCSD
High-speed circuit switched data.

HSDPA
High-speed downlink packet access.
This is a mobile telephony protocol, also called 3.5G (or “3½G”). Highspeed downlink packet access is a packet-based data service with data transmission up to 8-10 Mbit/s (and 20 Mbit/s for MIMO systems) over a 5 MHz bandwidth in W-CDMA downlink. HSDPA implementation includes adaptive modulation and coding (AMC), multiple-input multiple- output (MIMO), hybrid automatic repeat request (HARQ), fast scheduling, fast cell search, and advanced receiver design.

HSUPA
High speed uplink packet access utilizes the same techniques as HSDPA in terms of link adaptation on the modulation deployed and HARQ to improve the uplink and therefore create synchronous data transmissions of up to 5.7 Mbit/s. A few differences are in the way the scheduling works in order to service all the devices that upload data from the network and the reduced modultion schemes.

HTTP and HTTPS
Hypertext transfer protocol (HTTP) is a communications protocol designed to transfer information between computers over the World Wide Web. HTTPS is HTTP using a secure socket layer (SSL). SSL is an encryption protocol invoked on a web server that uses HTTPS.

Hz
Hertz.
The frequency measurement unit equal to one cycle per second.