This glossary includes key terms of the IoT (Internet of Things) & M2M (machine-to-machine) communications industry, including wireless and cellular technologies spanning many different markets. It is updated to present current terminology and usage. Your participation and feedback are most welcome—to submit comments, new entries, or suggestions, contact us today.

# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
There are 25 names in this directory beginning with the letter H.
HaaS
Hadoop as a Service.
Hadoop
A Java-based, distributed programming framework for processing large data sets. An application can be broken down into numerous small parts, called fragments or blocks, that can be run on any node in the cluster. Hadoop is free and part of the Apache project, sponsored by the Apache Software Foundation.
Hadoop as a Service (Haas)
The running of Hadoop in the Cloud, requiring no local hardware or IT infrastructure. The service is typically elastic, allowing the adding or removal of nodes depending on user needs.
Hadoop Distributed File System (HDFS)
The primary distributed storage used by Hadoop applications. A HDFS cluster has a NameNode that manages the file system metadata and DataNodes to store the actual data.
Haptic Technology or Haptics
Also referred to as Haptics or “touch feedback,” haptic technology applies tactile sensations to human interactions with machines. The simplest example is the actuator that vibrates a cell phone, but more advanced haptics can detect the pressure applied to a sensor, affecting the response.
HDFS
Hadoop Distributed File System.
Heating, Ventilation, and Air Conditioning (HVAC)
Sometimes grouped with refrigeration as HVACR, these systems cover both vehicular and indoor building comfort control.
HEM
Home Energy Management.
HEMS
Home Energy Management System.
Heterogeneous Network (HetNet)
Small cell networks using both macro and small cells. HetNets allow mobile operators to better utilize their data networks’ capacity.
HetNet
Heterogeneous Network.
High Speed Downlink Packet Access (HSDPA)
This increases the capacity of UMTS/3G bandwidth to allow for faster download speeds for connected devices.
High Speed Packet Access
An improvement made to transfer speeds over 3G technology through the addition of two new protocols; HSDPA and HSUPA. It offers potential downlink speeds of 14 Mbit/s and downlink of 5.76 Mbit/s.
High Speed Uplink Packet Access (HSUPA)
An improvement made to UMTS to enable faster uploading of data from devices, increasing capacity and throughput while reducing delay.
HLR
Home Location Register.
Home Automation
The automation of certain activities within a household. This can include automated control of lights, doors, and air conditioning, for example.
Home Energy Management
The process of increasing energy efficiency and savings for residential customers, ideally within a larger smart-grid environment.
Home Energy Management System (HEMS)
Equipment and services that optimize energy use in a residential setting while maintaining comfort. A HEMS includes smart appliances, home gateways, smart meters, and information exchange with local utilities via a smart grid.
Host
Computers that provide (or host) certain services or resources within a network that other participants within the network can then access and use. Hosts are the hardware basis for servers, as servers are run on hosts. Often times, they are the central point in a company’s data processing process.
HSDPA
High-Speed Downlink Packet Access.
HSPA
High-Speed Packet Access.
HSPA+
Enhanced or Evolved High-Speed Packet Access.
HSUPA
High-Speed Uplink Packet Access.
HVAC
Heating, Ventilation, and Air Conditioning systems.
Hybrid Cloud
A mix of public and private cloud. The distribution of services through private or public channels is decided upon by the users.