DEFINITIONS - 7

Gaussian frequency shift keying (GFSK): A modulation scheme in which the data are first filtered by a
Gaussian filter in the baseband and then modulated with a simple frequency modulation.
group: The entities in a wireless network, e.g., an access point (AP) and its associated stations (STAs), or all
the STAs in an independent basic service set (IBSS) network.
group address: A medium access control (MAC) address that has the group bit equal to 1. Syn: multicast
address.
group addressed: When applied to a medium access control (MAC) service data unit (MSDU), it is an
MSDU with a group address as the destination address (DA). When applied to a MAC protocol data unit
(MPDU), it is an MPDU with a group address in the Address 1 field. Syn: multicast.
Group Key Handshake: A group key management protocol defined by this standard. It is used only to
issue a new group temporal key (GTK) to peers with whom the local station (STA) has already formed
security associations.
group master key (GMK): An auxiliary key that might be used to derive a group temporal key (GTK).
group temporal key (GTK): A random value, assigned by the group source, which is used to protect group
addressed medium access control (MAC) protocol data units (MPDUs) from that source. The GTK might be
derived from a group master key (GMK).
hidden station (STA): A STA whose transmissions are not detected using carrier sense (CS) by a second
STA, but whose transmissions interfere with transmissions from the second STA to a third STA
homogenous extended service set (ESS): A collection of basic service sets (BSSs), within the same
extended service set (ESS), in which every subscription service provider network (SSPN) or other external
network reachable at one BSS is reachable at all of them.
hybrid coordination function (HCF): A coordination function that combines and enhances aspects of the
contention-based and contention-free access methods to provide quality-of-service (QoS) stations (STAs)
with prioritized and parameterized QoS access to the wireless medium (WM), while continuing to support
non-QoS STAs for best-effort transfer. The HCF includes the functionality provided by both enhanced
distributed channel access (EDCA) and HCF controlled channel access (HCCA). The HCF is compatible
with the distributed coordination function (DCF) and the point coordination function (PCF). It supports a
uniform set of frame formats and exchange sequences that STAs might use during both the contention
period (CP) and the contention-free period (CFP).
hybrid coordinator (HC): A type of coordinator, defined as part of the quality-of-service (QoS) facility,
that implements the frame exchange sequences and medium access control (MAC) service data unit
(MSDU) handling rules defined by the hybrid coordination function (HCF). The HC operates during both
the contention period (CP) and contention-free period (CFP). The HC performs bandwidth management
including the allocation of transmission opportunities (TXOPs) to QoS stations (STAs). The HC is
collocated with a QoS access point (AP).
hybrid coordination function (HCF) controlled channel access (HCCA): The channel access mechanism
utilized by the hybrid coordinator (HC) to coordinate contention-free media use by quality-of-service (QoS)
stations (STAs) for downlink individually addressed, uplink, and direct-link transmissions.