There are large companies like Nokia, LG and Samsung who have end-to-end capabilities. Apart from them, the smaller players depend on the ecosystem to compete with the big players.
The mobile handset ecosystem consists of :
The brand owners, who market the mobile phones under the own brand name. Like Asus, HTC
The contract manufactures, mostly based out of China/Tiwan. Like Flextronics
The design houses, who provide ready to manufacture mobile handset designs and also customization service. Like MediaTek and Infineon.
Chipset manufactures , they provide the mobile chipsets along with reference designs. Like Freescale and TI.
The OS (operating System) vendors. Like Windows CE (Microsoft), Symbian (Nokia), Android (Google).
The alphabetic list of Handset brands being marketed in India, as of December 2009, are:
Asus
Benq
Bird
Blackberry
Essar Group's MobileStore
Fly
HP, iPAQ
HTC
i-mate
Intex Technologies (India) Ltd.
LG
Micromax Informatics Ltd
Motorola
Nokia
O2
PalmOne
Sagem
Samsung
Siemens
SonyEricsson
Spice
Trium, Mitsubishi
VIDEOCON Ltd.