A concept of a multihop ad hoc network and associated algorithms for adapti
ve clustering in wireless ad hoc networks are presented in this paper. The
algorithms take into account the connectivity of the stations as well as th
e quality of service requirements, The concept of a centralised ad hoc netw
ork is adopted, in which a cluster is defined by a Central Controller grant
ing access to the radio interface to all terminals in its cluster. By these
means the CC contributes to provide quality of service guarantees to the u
sers. This concept is also used in the HipcrLAN/2 (HL/2) Home Environment E
xtension (HEE), an ad hoc wireless LAN standardised by the European Telecom
munications Standardisation Institute (ETSI). The HEE is restricted to one
single cluster. It is shown in this article how the network can be extended
over several clusters by the introduction of so-called "forwarding" statio
ns. These forwarders interconnect the clusters and enable multihop connecti
ons of users roaming in different clusters. A solution is presented to ensu
re, as far as possible, an interconnection of clusters by means of the clus
tering algorithm. (C) 2001 Elsevier Science B.V. All rights reserved.