Wireless VoIP phone architecture and hardware requirements

Abstract

A handheld set implementation using a wireless VoIP protocol is an inexpensive and effective solution to cellular phones. Although network to network interface has already been implemented using VoIP, the bottle-neck for wireless network is usually at the wireless access interface. Extending the use of IP packet to the edge benefits companies with cost management and effectively raise its customer base. A VoIP implemented in a handheld phone will deliver a more robust solution of VoIP from user to end user interface. Implementation of a handheld wireless VoIP handheld set needs new hardware. Functionality in wireless chipsets has been divided between MAC/DSP/RF layers. The medium access controller (MAC) layer serves as the media information interface and controller. The wireless VoIP custom chip in this design integrates those functionalities to implement the handheld wireless VoIP handset. The Physical layer includes the base-band signal processing functions and the RF front-end circuitry, provides the necessary filtering and variable gain, and signal converter functions. With the MAC and base-band DSP functions at the back-end of the physical layer having been fully digitized, these functions may be integrated onto a single digital chip. Vendors then provide the front-end physical layer functions, RF and analogue circuits on RF chips, usually incorporating minimal digital functionality while the back end of the functions can be implemented more efficiently using the DSP technology.