Zero-loss front end for wireless communication

#The present invention relates to wireless communication and, more particularly, to a low-cost, zero-loss front end for applications such as wireless LAN (WLAN).

#WLAN is just beginning to enjoy a growing momentum in the marketplace as more and more users take advantage of the freedom to access their data wirelessly where the data is most useful. Significant recent advances in RF technology underpin this wireless networking revolution.

#Conventional designs of the half-duplex radios employed in WLAN and in other, similar applications use the same antennas for both reception and transmission. One such design, that uses antenna diversity for both transmission and reception paths, is illustrated in FIG. 1, which is adapted from PCT application WO 02/31999. (Note that WO 02/31999 is incorporated by reference for all purposes as if fully set forth herein.) FIG. 1 shows a wireless communication device 100 that includes a transmitter front end 130 and a receiver front end 132. Transmitter front end 130 includes an amplifier 102, an up-converter 104, an automatic gain control (AGC) amplifier 106 and a power amplifier 108. Receiver front end 132 includes an amplifier 112, a down-converter 114, an AGC amplifier 116 and a low noise amplifier 118. A signal 140 to be transmitted is supplied as an input baseband (BB) frequency signal or as an input intermediate frequency (IF) signal from a modem (not shown). Signal 140 is frequency up-converted by up-converter 104. A received signal 142, as down-converted by down-converter 114, is provided as an output BB or IF signal to the modem. A voltage-controlled oscillator (VCO) 122 controlled by a phase lock loop (PLL) 120 is a synthesized frequency source that generates the local oscillator frequencies for up-converter 104 and down-converter 114.

#The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

#FIGS. 1 and 2 illustrate prior art wireless communication devices;

#FIG. 3 illustrates a wireless communication device of the present invention.

#The present invention is of a wireless communication device that can be used to decrease the cost per capacity of the associated wireless system. Specifically, the present invention can be used to decrease the number of access points needed for a WLAN of a given capacity. In addition, the devices of the present invention cost less and consume less power than comparable prior art devices.

#The principles and operation of a wireless communication device according to the present invention may be better understood with reference to the drawings and the accompanying description.

#Returning now to the drawings, FIG. 3 illustrates a wireless communication device 300 of the present invention. Like prior art device 200, device 300 includes amplifier 102, up-converter 104, AGC amplifier 106, power amplifier 108 and a transmit antenna 328 for transmission of BB or IF signal 140; amplifier 112, down-converter 114 and AGC amplifier 116 for reception of BB or IF signal 142; and PLL 120 and VCO 122 for generating the local oscillator frequencies for up-converter 104 and down-converter 114.