WO2010029452A1

WO2010029452A1 - System and method dynamically switched dual-mode rf transceiver

Info

Publication number: WO2010029452A1
Application number: PCT/IB2009/053557
Authority: WO
Inventors: Alan Yeo Chin Leong
Original assignee: Nxp B.V.
Priority date: 2008-09-12
Filing date: 2009-08-12
Publication date: 2010-03-18

Abstract

A dual-mode transceiver system for switching operating modes. The dual-mode transceiver system includes a baseband integrated circuit (IC), a radio frequency(RF) IC (RFIC), and a dual-mode apparatus. The baseband IC generates a baseband signal. The RFIC receives the baseband signal from the baseband IC and generates a modulated RF signal for transmission. The dual-mode apparatus performs a frequency spectrum analysis, operates in a frequency-hopping mode at a first transmission power according to the frequency spectrum analysis, and operates in a fixed frequency mode at a second transmission power according to the frequency spectrum analysis.

Description

SYSTEM AND METHOD DYNAMICALLY SWITCHED DUAL-MODE RF

TRANSCEIVER

Recent years have seen an explosion of products for wireless applications. The introduction of digital transmission protocols has enabled digital wireless systems to overcome the shortcomings of analog wireless systems and the line-of-sight/range limitations of infrared (IR) based solutions. Wireless applications range from wireless local area network (WLAN) clients and Access Points to simple garage door openers and home automation/security components. With such a proliferation of wireless products, competition for the limited available frequency spectrum continues to increase dramatically. Throughout the world unlicensed bands exist which enable a mass propagation of wireless devices into the market. However, unlicensed bandwidth does not equate to unregulated bandwidth. Thus, manufacturers are bound to ensure their wireless devices conform to regional and/or national regulations.

Spread spectrum modulation techniques have become more common in recent years. Spread spectrum enables a signal to be transmitted across a frequency band that is much wider than the minimum bandwidth that might otherwise be used to transmit the information signal. In spread spectrum systems, a transmitter "spreads" the energy originally concentrated in a narrowband across a number of frequency band channels on a wider frequency spectrum. Compared to a fixed frequency mode, benefits of spread spectrum include improved privacy, decreased narrowband interference, and increased signal capacity.

Spread-spectrum technology is designed to trade off bandwidth efficiency for reliability, integrity and security. In other words, more bandwidth is consumed to produce a "louder" and thus easier to detect broadcast signal. But to the unintended receiver, the spread-spectrum signal appears as noise. However, the bandwidth- spreading characteristics of spread- spectrum allow sharing of the bandwidth. For example, in Frequency-Hopping Spread Spectrum (FHSS) technology, a narrowband carrier hops among several frequencies at a specific rate and sequence as a way of avoiding interference. Hence, FHSS is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both the transmitter and the receiver. Additionally, one wireless device operating in FHSS mode has a hopping pattern completely different and orthogonal (never colliding) to another wireless device operating in FHSS mode.

Fig. IA depicts a schematic block diagram of a spread spectrum bandwidth 100 of frequency hopping links. The y-axis depicts available channels (frequency slots) in the spread spectrum bandwidth 100. The x-axis depicts the available time slots in the spread spectrum bandwidth 100. In a given time slot, no two links (differentiated by the depicted patterns) share the same channel (frequency slot). Likewise for a given channel, no two links occupy the same time slot.

Fig. IB depicts a schematic block diagram of a fixed frequency link 102 among the frequency hopping links of the spread spectrum bandwidth 100 of Fig. IA. In other words, Fig. IB illustrates the presence of a fixed frequency (non-spread spectrum) system operating among other FHSS links. Details of a fixed frequency system are described in more detail below with reference to Fig. 2B.

Fig. 2A depicts a schematic block diagram of a high-power spread spectrum system 200. The operation of the spread spectrum system 200 is depicted with reference to the spread spectrum bandwidth 100 of frequency hopping links of Fig. IA. The spread spectrum system 200 includes a high-power transceiver 202, a radio frequency (RF) power amplifier 204, a transmit/receive (TX/RX) switch 206, and a termination module 208. The spread spectrum system 200 also includes an antenna 210, RX transmission lines 222, TX transmission lines 224, and a control line 226. The high-power transceiver 202 includes a memory device 212, a processor 214, a baseband integrated circuit (IC) 216, and an RFIC 218. The memory device 212 and processor 214 enable the high-power transceiver 202 to perform operations related to transmitting and receiving signals in the spread spectrum system 200. The baseband IC 216 generates a baseband signal. The RFIC 218 upconverts the baseband signal generated by the baseband IC 216 to generate an RF output signal. The RF power amplifier 204 amplifies an input RF signal to increase the amount of RF output power delivered to a load. In other words, the RF power amplifier 204 boosts the transmitted RF level of a transmit signal. The RF power amplifier is powered by a voltage source VCC 220. In the spread spectrum system 200, the RF output signal generated by the RFIC 218 is amplified by the RF power amplifier 204 and switched through the TX/RX switch 206. The high-power transceiver 202 controls the TX/RX switch 206 with the control line 226. The TX/RX switch 206 toggles/switches between transmit and receive cycles. When in the receiving mode, the incoming signal is switched around the RF power amplifier 204, since the RF power amplifier 204 is a unidirectional device. In other words, when the spread spectrum system 200 receives a signal, the TX/RX switch 206 switches to the RX position and the RX transmission lines 222 carry the received signal to the high-power transceiver 202, bypassing the RF power amplifier 204. When the spread spectrum system 200 transmits a signal, the high-power transceiver 202 generates the RF output signal. The TX transmission lines 224 then carry the RF output signal to the RF power amplifier 204, and from the RF power amplifier 204 to the TX/RX switch 206. The TX/RX switch switches to the TX position and the RF output signal is carried to the termination module 208.

Fig. 2B depicts a schematic block diagram of a low-power fixed frequency system 228. The operation of the fixed frequency system 228 is depicted with reference to the fixed frequency link 102 of Fig. IB. Compared to the spread spectrum system 200, the fixed frequency system 228 occupies a distinct band of frequency when it is operating, in effect creating a reserved zone in the spread spectrum band.

The fixed frequency system 228 includes a low-power transceiver 230, RX transmission lines 244, TX transmission lines 246, a termination module 240, and an antenna 242. The low-power transceiver 230 includes a memory device 232, a processor 234, a baseband IC 236, and an RFIC 238. Many of the components of the fixed frequency system 228 are substantially similar to the components of the spread spectrum system 200 and operate in a substantially similar manner, except as described below.

One of the differences between the fixed frequency system 228 and the spread spectrum system 200 is that the RF power amplifier 204 is omitted from the fixed frequency system 228. Thus, the transmit signals from the fixed frequency system 228 are not amplified following generation of the RF output signal by the RFIC 238, and the RX and TX transmission lines 244 and 246 are commonly connected to the termination module 240.

By regulation, more power is available for transmissions in frequency- hopping devices such as the spread spectrum system 200. However, as more and more FHSS devices flood the market and contend for an increasingly limited bandwidth, the probability of collisions between FHSS devices increases, resulting in more errors and an increase in retransmissions, all of which ultimately results in an overall reduction in system efficiency for frequency-hopping devices such as the spread spectrum system 200. One solution is to identify a frequency range (channel) in the operating bandwidth which is determined to be relatively interference free, select the interference- free frequency, and cease hopping in the spread spectrum system 200. However, operating a spread spectrum system 200 without the hopping function is interpreted as an implementation of the fixed frequency system 228. By regulation (i.e., Federal Communication Commission (FCC), European Telecommunications

Standards Institute (ETSI), etc.), a fixed frequency system 228 generally must operate at a lower transmission power than a spread spectrum system 200. Consequently, a spread spectrum system 200 that selects and operates only on an interference- free frequency is no longer considered certified as being compliant with regional and/or national regulations.

Embodiments of a system are described. In one embodiment, the system is a dual-mode transceiver system. The dual-mode transceiver system includes a baseband integrated circuit (IC), a radio frequency (RF) IC (RFIC), and a dual-mode apparatus. The baseband IC generates a baseband signal. The RFIC receives the baseband signal from the baseband IC and generates a modulated RF signal for transmission. The dual-mode apparatus performs a frequency spectrum analysis, operates in a frequency-hopping mode at a first transmission power according to the frequency spectrum analysis, and operates in a fixed frequency mode at a second transmission power according to the frequency spectrum analysis. Other embodiments of the system are also described.

Embodiments of a method are also described. In one embodiment, the method is a method for operating a dual-mode transceiver. The dual-mode transceiver method includes scanning for features of a frequency spectrum. The features of the frequency spectrum include interfering channels and clean channels. The clean channels include substantially less interference than the interfering channels. The dual-mode transceiver method also includes analyzing the features of the scanned frequency spectrum. The dual-mode transceiver method also includes operating in a frequency-hopping mode at a first transmission power according to the frequency spectrum analysis. The dual-mode transceiver method also includes operating in a fixed frequency mode at a second transmission power according to the frequency spectrum analysis. Other embodiments of the method are also described. Embodiments of an apparatus are also described. In one embodiment, the apparatus is a dual-mode apparatus. The dual-mode apparatus includes an RFIC, an RF power amplifier, and a TX path switch. The radio frequency RFIC receives a baseband signal from a baseband IC and generates a modulated RF signal for transmission. The RF power amplifier amplifies the modulated RF signal to increase an RF output power associated with the modulated RF signal. The TX path switch switches between a bypass position and a pass-through position according to a spectrum analysis. The bypass position routes the modulated RF signal from the RFIC, through the TX path switch, and to the RX transmission line in a fixed frequency mode. The pass-through position routes the modulated RF signal from the RFIC, through the TX path switch, and to the RF power amplifier in a frequency- hopping mode. Other embodiments of the apparatus are also described.

Other aspects and advantages of embodiments of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrated by way of example of the principles of the invention.

Fig. IA depicts a schematic block diagram of a spread spectrum bandwidth of frequency hopping links.

Fig. IB depicts a schematic block diagram of a fixed frequency link among the frequency hopping links of the spread spectrum bandwidth of Fig. IA.

Fig. 2A depicts a schematic block diagram of a high-power frequency- hopping system. Fig. 2B depicts a schematic block diagram of a low-power fixed frequency system.

Fig. 3 depicts a schematic block diagram of one embodiment of a dynamically switched dual-mode transceiver system. Fig. 4 depicts a schematic flow chart diagram of one embodiment of a mode switching method for use with the dual-mode apparatus of Fig. 3.

Fig. 5 depicts a schematic flow chart diagram of one embodiment of a fixed frequency channel switching method for use with the dual-mode apparatus of Fig. 3. Throughout the description, similar reference numbers may be used to identify similar elements.

Fig. 3 depicts a schematic block diagram of one embodiment of a dynamically switching dual-mode transceiver system 300. In one embodiment, the dual-mode transceiver system 300 is a component of a user equipment (UE). A UE may include a Bluetooth device, a cell-phone, a cordless phone, a garage door opener, a remote controller, and other similar wireless devices. Alternatively, the dual-mode transceiver system 300 is a component of a base station (BS) such as a data tower BS, a cordless phone BS, a garage door opener BS, or a desktop computer, for example, in a Bluetooth environment. Although the depicted dual-mode transceiver system 300 is shown and described herein with certain components and functionality, other embodiments of the dual-mode transceiver system 300 may be implemented with fewer or more components or with less or more functionality. In some embodiments, the components of the dual-mode transceiver system 300 are integrated on a single integrated circuit (IC). In some embodiments, the components of the dual-mode transceiver system 300 are partially integrated on one or more ICs.

The dual-mode transceiver system 300 includes a dual-mode transceiver 302, a transmit (TX) path switch 304, a Radio Frequency (RF) power amplifier 306, a power amplifier (PA) power switch 308, a dual-mode receiver/transmitter (RX/TX) mode switch 310, a termination module 312, and at least one antenna 314. Additionally, the dual-mode transceiver system 300 includes TX transmission lines 334, RX transmission lines 336, dual-mode control lines 338, and a voltage source VCC 340. Although the depicted dual-mode transceiver system 300 is shown and described herein with certain components and functionality, other embodiments of the dual-mode transceiver system 300 may be implemented with fewer or more components or with less or more functionality.

In one embodiment, the dual-mode transceiver 302 is a single transceiver. Alternatively, the dual-mode transceiver 302 includes a separate wireless transmitter and receiver. The transmitter function of the dual-mode transceiver 302 transmits data packets associated with both a frequency-hopping mode and a fixed frequency mode. Likewise, the receiver function of the dual-mode transceiver 302 receives data packets associated with both the frequency-hopping mode and the fixed frequency mode.

As illustrated, the dual-mode transceiver 302 includes a dual-mode apparatus 316, a memory device 318, a processor 320, a baseband IC 322, an RFIC 324, and at least one bus interface 332. In one embodiment, the bus interface 332 facilitates communications related to the dual-mode apparatus 316 and/or protocols related to operating in a frequency- hopping mode and to operating in a fixed frequency mode. In particular, the bus interface 332 enables the dual-mode apparatus 316 to perform dual-mode switching protocols executing on the dual-mode transceiver system 300, including processing clear channel detection and dual-mode switching commands, as well as storing, sending, and receiving data packets associated with the clear channel detection and dual-mode switching operations of the dual-mode apparatus 316. Other embodiments may use another type of data transmission channel, instead of the bus interface 332.

In some embodiments, the dual-mode apparatus 316 enables a UE and/or a BS to switch between a frequency- hopping mode and a fixed channel mode on a single dual-mode transceiver system 300. The dual-mode apparatus 316 scans the spectrum associated with the dual-mode transceiver system 300 for clear channels and selects a clear channel for the wireless transmission and reception of data. Thus, the dual-mode apparatus 316 enables the dual-mode transceiver system 300 to transmit at a maximum, or relatively high, transmission power during a selected frequency- hopping mode, and enables the dual-mode transceiver system 300 to automatically adjust the transmission power down to within a regulation level when switching to and operating in a fixed frequency mode. Furthermore, the dual-mode apparatus 316 allows the dual-mode transceiver 300 to seamlessly switch back and forth between the frequency-hopping mode and the fixed frequency mode. Additionally, some embodiments of the dual-mode apparatus 316 provide an interface for a user to select between the frequency-hopping mode and the fixed frequency mode. The illustrated dual-mode apparatus 316 includes a scanner 326, a spectrum analyzer 328, and a user interface 330.

In some embodiments, the scanner 326 scans the frequency spectrum associated with the dual-mode transceiver system 300 operating in a frequency- hopping mode and/or the frequency spectrum associated with the dual-mode transceiver system 300 operating in a fixed frequency mode. In some embodiments, the scanner 326 performs a background scan while the dual-mode transceiver system 300 performs transmit and receive operations associated with the frequency- hopping mode and/or fixed frequency mode.

In some embodiments, the spectrum analyzer 328 analyzes the scanned spectrum associated with the frequency-hopping mode and/or the fixed frequency mode. In some embodiments, the spectrum analyzer 328 analyzes the scanned spectrum for one or more clear channels that are available in the scanned spectrum. In one embodiment, the user interface 330 allows a user to interface with the dual-mode apparatus 316. In some embodiments, the user interface 330 allows a user to configure the operations and functions of the dual-mode apparatus 316. In some embodiments, the user interface 330 allows a user to manually switch the operation of the dual-mode transceiver 302 from a frequency-hopping mode to a fixed frequency mode. Alternatively, the user interface 330 allows a user to manually switch the operation of the dual-mode transceiver 302 from a fixed frequency mode to a frequency-hopping mode. In one embodiment, the memory device 318 is utilized by the dual- mode apparatus 316 to perform clean channel detection and switching mode operations and other related functions. Alternatively, a separate memory device may be embedded in the dual-mode apparatus 316 and/or other components of the dual- mode transceiver 302. In some embodiments, the memory device 318 is a random access memory (RAM) or another type of dynamic storage device. In some embodiments, the memory device 318 is a read-only memory (ROM) or another type of static storage device. In some embodiments, the illustrated memory device 318 is representative of both RAM and static storage memory within the dual-mode transceiver 302. In some embodiments, the memory device 318 is content-addressable memory (CAM). In other embodiments, the memory device 318 is an electronically programmable read-only memory (EPROM) or another type of storage device. Additionally, some embodiments store protocols and/or instructions related to clean channel detection and mode switching operations as firmware such as embedded code, basic input/output system (BIOS) code, and/or other similar code.

In one embodiment, the processor 320 is utilized by the dual-mode apparatus 316 to perform clean channel detection and mode switching operations and other related functions. Alternatively, a separate processor may be embedded in the dual-mode apparatus 316 and/or other components of the dual-mode transceiver 302. In some embodiments, the processor 320 is a central processing unit (CPU) with one or more processing cores. In other embodiments, the processor 320 is a network processing unit (NPU) or another type of processing device such as a general purpose processor, an application specific processor, a multi-core processor, or a microprocessor. In general, the processor 320 executes one or more instructions to provide operational functionality to the dual-mode transceiver system 300. Protocols and/or instructions related to clean channel detection and the modes of operation may be stored locally in the processor 320 or in the memory device 318. Alternatively, the instructions may be distributed across one or more devices such as the processor 320, the memory device 212, and/or another data storage device.

In one embodiment, the baseband IC 322 generates a baseband signal for transmission. The baseband IC 322 provides baseband signal processing and protocol hardware for use in a spread spectrum device. The baseband IC 322 may include an embedded processor with firmware that implements certain wireless protocols such as the Bluetooth protocols.

In some embodiments, the RFIC 324 generates an RF output signal from the baseband signal generated by the baseband IC 322. In other words, the RFIC 324 may include a radio frequency modulator (not shown) to upconvert a channelized Intermediate Frequency (IF) signal to provide a wideband RF output signal. The RFIC 324 may include amplifiers, mixers, modulators/demodulators, oscillators, synthesizers and switches (not shown) to provide the operations and functions of generating an RF output signal for transmission. In some embodiments, the RF output signal is carried from the dual-mode transceiver 302 to the TX path switch 304 over the TX transmission lines 334.

In one embodiment, the dual-mode transceiver 302 utilizes the dual- mode control lines 338 to control the TX path switch 304, the PA power switch 308, and the RX/TX mode switch 310 in relation to a mode switching operation. In some embodiments, the dual-mode transceiver 302 controls the TX path, the PA power, and the RX/TX mode switches 304, 308, and 310 in conjunction with the dual-mode apparatus 316.

In one embodiment, the TX path switch 304 switches the outgoing path of the RF output signal between going through the RF power amplifier 306 and going over the RX transmission lines 336. In some embodiments, the PA power switch 308 switches the power supply to the RF power amplifier 306 on or off. In some embodiments, the dual-mode RX/TX mode switch 310 switches between TX and RX cycles. In some embodiments, the dual-mode RX/TX mode switch 310 holds the switch in the TX position or the RX position over multiple TX and/or RX cycles.

For example, when the operation mode of the dual-mode transceiver 302 is switched from a frequency- hopping mode to a fixed frequency mode, the TX path switch 304 is switched from the path through the RF power amplifier 306 to a path over the RX transmission lines 336, thus bypassing the amplification of the transmit signal via the RF power amplifier 306. Likewise, the PA power switch 308 is switched from the on position to the off position, opening the connection between the VCC voltage source 340 and the RF power amplifier 306 and switching the RF power amplifier 306 off. Additionally, the dual-mode RX/TX mode switch 310 is held in the RX position for all TX and RX cycles associated with the fixed frequency mode. Thus, when switching from a frequency-hopping mode to a fixed frequency mode, the transmission power may be dynamically adjusted to a regulated transmission power associated with the fixed frequency mode.

Alternatively, when the operation mode of the dual-mode transceiver 302 is switched from a fixed frequency mode to a frequency- hopping mode, the TX path switch 304 is switched from the path over the RX transmission lines 336 to the path through the RF power amplifier 306, thus amplifying any transmit signal via the RF power amplifier 306. Additionally, the PA power switch 308 is switched from the off position to the on position, closing the connection between the VCC voltage source 340 and the RF power amplifier 306 and switching the RF power amplifier 306 on. The dual-mode RX/TX mode switch 310 is switched to the TX position for each TX cycle and to the RX position for each RX cycle. Thus, when switching from a fixed frequency mode to a frequency-hopping mode, the transmission power may be dynamically increased for operation in the frequency-hopping mode.

The order in which the TX path, the PA power, and the RX/TX mode switches 304, 308, and 310 are described above does not indicate the actual order in which each switch is switched in a mode switching operation. In some embodiments, the switches 304, 308, and 310 are switched simultaneously. Alternatively, the switches 304, 308, and 310 may be switched in a certain sequence.

In one embodiment, the termination module 312 may implement an RF filter (not shown) and/or antenna matching circuitry (not shown) to properly terminate and match the output impedance of the TX and RX transmission lines 334 and 336 to the input impedance of the antenna 314. An RF filter is an electrical circuit designed to have specific characteristics with respect to the transmission or attenuation of various frequencies that may be applied to it. The RF filter may include a high-pass filter, a low-pass filter, and/or a band-pass filter. The termination module 312 may implement an antenna matching network to match an output impedance of the RX and TX transmission lines 334 and 336 to an input impedance of the antenna 314. The antenna 314 then transmits the wideband RF output signal to a receiver (not shown).

Alternatively, the antenna 314 receives an RF output signal from another transmitter. In some embodiments, the antenna 314 includes multiple antennas that the dual-mode transceiver 302 utilizes in a multiple-in multiple-out (MIMO) implementation of the dual-mode transceiver system 300. Fig. 4 depicts a schematic flow chart diagram of one embodiment of a mode switching method 400 for use with the dual-mode apparatus 300 of Fig. 3. Although the mode switching method 400 is described in conjunction with the dual- mode apparatus 300 of Fig. 3, some embodiments of the method 400 may be implemented with other types of dual-mode apparatuses. At block 402, the scanner 326 scans the frequency spectrum. In some embodiments, the scanner 326 scans the frequency spectrum for clean channels in the frequency spectrum. At block 404, the spectrum analyzer 326 analyzes the features of the scanned frequency spectrum. In some embodiments, the spectrum analyzer 326 analyzes the scanned frequency spectrum for clean channels. In some embodiments, the spectrum analyzer 326 ranks the channels in the frequency spectrum according to the level of interference in each scanned channel.

At block 406, the dual-mode apparatus 316 determines whether to switch the operating mode of the dual-mode transceiver system 300. In some embodiments, the dual-mode apparatus 316 determines whether to switch the operating mode of the dual-mode transceiver system 300 from a frequency-hopping mode to a fixed frequency mode. Alternatively, the dual-mode apparatus 316 determines whether to switch the operating mode of the dual-mode transceiver system 300 from a fixed frequency mode to a frequency-hopping mode. As one example, in some embodiments, the dual-mode apparatus 316 determines whether collisions associated with wireless communications while the dual-mode transceiver system 300 is operating in the frequency-hopping mode exceed a predetermined collision threshold. If the dual-mode apparatus 316 determines not to switch modes, then at block 408 the dual-mode apparatus 316 maintains the current operating mode of the dual-mode transceiver 300, and the mode switching method 400 returns to block 402. For example, if the dual-mode transceiver 300 is currently operating in the frequency- hopping mode and determines that the collisions do not exceed the collision threshold, then the dual-mode apparatus 316 maintains the dual-mode transceiver 300 in the frequency-hopping mode.

If the dual-mode apparatus 316 determines to switch modes, then at block 408, then the dual-mode apparatus 316 initiates a process to switch operating modes. For example, if the dual-mode transceiver 300 is currently operating in the frequency-hopping mode and determines that the collisions exceed the collision threshold, then the dual-mode apparatus 316, in conjunction with the spectrum analyzer 328, switches the operating mode of the dual-mode transceiver system 300 from the frequency-hopping mode to the fixed frequency mode.

In one embodiment, at block 410 the dual-mode apparatus 316 automatically adjusts the transmit power of the dual-mode transceiver system 300 to within a regulation level for the selected operating mode of the dual-mode transceiver system 300. According to the selected operating mode, at block 412, the dual-mode apparatus 316 controls the RX/TX mode switch 310. In the fixed frequency mode, the dual-mode apparatus 316 holds the RX/TX mode switch 310 in the RX position over multiple TX and RX cycles. In the frequency-hopping mode, the dual-mode apparatus 316 toggles the RX/TX mode switch 310 to the TX position for each TX cycle, and to the RX position for each RX cycle. At block 414, the dual-mode apparatus 316 controls the PA path switch

304. In the fixed frequency mode, the dual-mode apparatus 316 switches the PA path switch 304 to the RX transmission lines 336 so that the transmit and receive data packets are both carried from the antenna 314 to the dual-mode transceiver 302 over the RX transmission lines 336. Thus, the transmit data packets generated by the dual- mode transceiver 302 remain unamplified as they are dynamically routed to bypass the RF power amplifier 306. Alternatively, in the frequency-hopping mode, the dual- mode apparatus 316 switches the PA path switch 304 to pass the transmit data packets through the RF power amplifier 306. Thus, the transmit data packets generated by the dual-mode transceiver 302 are amplified before being transmitted by the antenna 314. At block 416, the dual-mode apparatus 316 controls the PA power switch 308. In the frequency-hopping mode, the dual-mode apparatus 316 switches and holds the PA power switch 308 closed. Holding the PA power switch 308 closed connects the VCC power source 340 to the RF power amplifier 306, thus powering the RF power amplifier 306. Alternatively, in the fixed frequency mode, the dual- mode apparatus 316 switches and holds the PA power switch 308 open. Holding the PA power switch 308 open disconnects the RF power amplifier 306 from the VCC power source 340, thus turning the RF power amplifier 306 off. The dual-mode transceiver method 400 then returns to block 402.

In some embodiments, at block 418, a user selects an operating mode via the user interface 330. According to the operating mode selected by the user, the dual-mode apparatus 316 controls the transceiver, PA path, and PA power switches 310, 304, and 308 appropriately. This allows a user to manually select the operating mode of the dual-mode apparatus 300.

Fig. 5 depicts a schematic flow chart diagram of one embodiment of a fixed frequency channel switching method 500 for use with the dual-mode apparatus 300 of Fig. 3. Although the channel switching method 500 is described in conjunction with the dual-mode apparatus 300 of Fig. 3, some embodiments of the method 500 may be implemented with other types of dual-mode apparatuses. At block 502, the scanner 326 scans the frequency spectrum. In some embodiments, the scanner 326 scans the frequency spectrum for clean channels in the frequency spectrum. At block 504, the spectrum analyzer 326 analyzes the features of the scanned frequency spectrum. In some embodiments, the spectrum analyzer 326 analyzes the scanned frequency spectrum for clean channels. In some embodiments, the spectrum analyzer 326 ranks the channels in the frequency spectrum according to the level of interference in each scanned channel.

At block 506, the dual-mode apparatus 316 determines whether to switch channels in the fixed frequency mode. In some embodiments, the dual-mode apparatus 316 determines whether collisions associated with a channel in the fixed frequency mode exceeds a predetermined collision threshold. In response to the collisions exceeding the collision threshold, the dual-mode apparatus 316, in conjunction with the spectrum analyzer 328, switches, at block 510, the currently used channel in the fixed frequency mode to a new channel with less interference, as determined by the analysis of the spectrum analyzer 328. Otherwise, at block 508, the dual-mode apparatus 316 maintains the current channel in the fixed frequency mode. The channel switching method 500 then returns to block 502.

In some embodiments, at block 512, a user selects a channel in the fixed frequency mode via the user interface 330. According to the channel selected by the user, the dual-mode apparatus 316 switches, at block 510, the currently used channel in the fixed frequency mode to a new channel. This allows a user to manually select the operating mode of the dual-mode apparatus 300.

Embodiments of the mode switching method 400 and the channel switching method 500 described with reference to Figs. 4 and 5 demonstrate an impact on the efficiency of switching between frequency- hopping and fixed frequency modes in the burgeoning wireless data communications field. Given that the number of wireless users worldwide continues to grow rapidly, the ability to design and deliver a wireless product that is robust in the face of other potentially interfering wireless devices offers an advantage in the competitive wireless market. To the user this provides a choice for a long-range mode with higher power (frequency-hopping mode) or a more robust short-range mode with lower power (fixed frequency mode). Thus, based on the dual-mode transceiver system 300, a single wireless product is able to provide dual-modes of wireless operation in multiple regions of the world while satisfying the power regulations of those different regions. Additionally, disabling power to the RF power amplifier 328 stage saves power consumption.

Although the operations of the method(s) herein are shown and described in a particular order, the order of the operations of each method may be altered so that certain operations may be performed in an inverse order or so that certain operations may be performed, at least in part, concurrently with other operations. In another embodiment, instructions or sub-operations of distinct operations may be implemented in an intermittent and/or alternating manner.

Although specific embodiments of the invention have been described and illustrated, the invention is not to be limited to the specific forms or arrangements of parts so described and illustrated. The scope of the invention is to be defined by the claims appended hereto and their equivalents.

Claims

CLAIMS:

1. A dual-mode transceiver system comprising: a baseband integrated circuit (IC) to generate a baseband signal; a radio frequency (RF) IC (RFIC) coupled to the baseband IC, the RFIC to receive the baseband signal from the baseband IC and to generate a modulated RF signal for transmission; and a dual-mode apparatus coupled to the baseband IC and the RFIC, the dual-mode apparatus to perform a frequency spectrum analysis, to operate in a frequency-hopping mode at a first transmission power according to the frequency spectrum analysis, and to operate in a fixed frequency mode at a second transmission power according to the frequency spectrum analysis.

2. The dual-mode transceiver system of claim 1, wherein the dual-mode apparatus is further configured to switch from the frequency-hopping mode to the fixed frequency mode according to the frequency spectrum analysis and to dynamically decrease an operating transmission power from the first transmission power to the second transmission power in response to the switch from the frequency- hopping mode to the fixed frequency mode.

3. The dual-mode transceiver system of claim 2, wherein the dual-mode apparatus is further configured to switch from the fixed frequency mode to the frequency-hopping mode according to the frequency spectrum analysis and to dynamically increase an operating transmission power from the second transmission power to the first transmission power in response to the switch from the fixed frequency mode to the frequency-hopping mode.

4. The dual-mode transceiver system of claim 3, further comprising a receiver/transmitter (RX/TX) mode switch connected to the dual-mode apparatus by a control line, wherein the dual-mode apparatus is further configured to hold the RX/TX mode switch in a receiver (RX) position over a plurality of transmission cycles in response to the switch from the frequency-hopping mode to the fixed frequency mode.

5. The dual-mode transceiver system of claim 4, wherein the dual mode apparatus is further configured to toggle the RX/TX mode switch between a transmit (TX) position and the RX position for each transmission cycle in response to the switch from the fixed frequency mode to the frequency-hopping mode.

6. The dual-mode transceiver system of claim 3, further comprising a transmit (TX) path switch connected to the dual-mode apparatus by a control line, wherein the dual-mode apparatus is further configured to hold the TX path switch in a bypass position over a plurality of transmission cycles in response to the switch from the frequency-hopping mode to the fixed frequency mode, wherein the TX path switch in the bypass position routes a transmit packet to bypass an RF power amplifier.

7. The dual-mode transceiver system of claim 6, wherein the dual-mode apparatus is further configured to hold the TX path switch in a pass-through position over a plurality of transmission cycles in response to the switch from the fixed frequency mode to the frequency-hopping mode, wherein the TX path switch in the pass-through position routes a transmit packet through the RF power amplifier.

8. The dual-mode transceiver system of claim 3, further comprising a power amplifier power switch connected to the dual-mode apparatus by a control line, wherein the dual-mode apparatus is further configured to hold the power amplifier power switch in a disable position over a plurality of transmission cycles in response to the switch from the frequency-hopping mode to the fixed frequency mode, wherein the power amplifier power switch in the disable position disables an RF power amplifier.

9. The dual-mode transceiver system of claim 8, wherein the dual-mode apparatus is further configured to hold the power amplifier power switch in an enable position over a plurality of transmission cycles in response to the switch from the fixed frequency mode to the frequency-hopping mode, wherein the power amplifier power switch in the enable position enables the RF power amplifier.

10. The dual-mode transceiver system of claim 1, wherein the dual-mode apparatus is further configured to maintain a current operating mode according to the frequency spectrum analysis.

11. The dual-mode transceiver system of claim 1 , wherein the dual-mode apparatus is further configured to switch from a current fixed frequency channel to a new fixed frequency channel for data transmissions in the fixed frequency mode according to the frequency spectrum analysis.

12. The dual-mode transceiver system of claim 1, wherein the dual-mode apparatus is further configured to maintain a current fixed frequency channel for data transmissions in the fixed frequency mode according to the spectrum analysis.

13. A dual-mode transceiver method, comprising: scanning for features of a frequency spectrum, wherein the features of the frequency spectrum comprise interfering channels and clean channels, wherein the clean channels comprise substantially less interference than the interfering channels; analyzing the features of the scanned frequency spectrum; operating in a frequency-hopping mode at a first transmission power according to the frequency spectrum analysis; and - operating in a fixed frequency mode at a second transmission power according to the frequency spectrum analysis.

14. The dual-mode transceiver method of claim 13, further comprising: switching from a frequency-hopping mode to a fixed frequency mode according to the frequency spectrum analysis; and dynamically decreasing an operating transmission power from the first transmission power to the second transmission power in response to switching from the frequency-hopping mode to the fixed frequency mode.

15. The dual-mode transceiver method of claim 14, further comprising: controlling a RX/TX mode switch to hold an RX position over a plurality of transmission cycles in response to switching from the frequency-hopping mode to the fixed frequency mode; controlling a TX path switch to hold a bypass position over a plurality of transmission cycles in response to switching from the frequency-hopping mode to the fixed frequency mode, wherein the TX path switch in the bypass position routes a transmit packet to bypass an RF power amplifier; and - controlling a power amplifier power switch to hold a disable position over a plurality of transmission cycles in response to switching from the frequency- hopping mode to the fixed frequency mode, wherein the power amplifier power switch in the disable position disables an RF power amplifier.

16. The dual-mode transceiver method of claim 13, further comprising: switching from the fixed frequency mode to the frequency-hopping mode according to the frequency spectrum analysis; and dynamically increasing an operating transmission power from the second transmission power to the first transmission power in response to switching from the fixed frequency mode to the frequency-hopping mode.

17. The dual-mode transceiver method of claim 16, further comprising: controlling a RX/TX mode switch to toggle between a transmit (TX) position and a receiver (RX) position for each transmission cycle in response to switching from the fixed frequency mode to the frequency-hopping mode; controlling a TX path switch to hold a pass-through position over a plurality of transmission cycles in response to switching from the fixed frequency mode to the frequency-hopping mode, wherein the TX path switch in the pass-through position routes a transmit packet through the RF power amplifier; and - controlling a power amplifier power switch to hold an enable position over a plurality of transmission cycles in response to switching from the fixed frequency mode to the frequency-hopping mode, wherein the power amplifier power switch in the enable position enables the RF power amplifier.

18. A dual-mode apparatus, comprising: a radio frequency (RF) IC (RFIC) to receive a baseband signal from a baseband IC and to generate a modulated RF signal for transmission; - an RF power amplifier coupled to the RFIC, the RF power to amplify the modulated RF signal to increase an RF output power associated with the modulated RF signal; and a transmit (TX) path switch connected between the RFIC, the RF power amplifier, and connected to a receiver (RX) transmission line, the TX path switch to switch between a bypass position and a pass-through position according to a spectrum analysis, wherein the bypass position routes the modulated RF signal from the RFIC, through the TX path switch, and to the RX transmission line in a fixed frequency mode, and wherein the pass-through position routes the modulated RF signal from the RFIC, through the TX path switch, and to the RF power amplifier in a frequency- hopping mode.

19. The dual-mode apparatus of claim 18, further comprising: a receiver/transmitter (RX/TX) mode switch connected to the TX path switch by the RX transmission line, connected to the RF power amplifier by a TX transmission line, and connected to a termination module by a TX/RX transmission line, the RX/TX mode switch to hold a receive (RX) position over a plurality of transmission cycles in the fixed frequency mode, and to toggle between a TX position for each transmit cycle and the RX position for each receive cycle in the frequency- hopping mode; and - a power amplifier power switch connected between the RF power amplifier by a power line and a power source by another power line, the power amplifier power switch to hold a disable position over a plurality of transmission cycles in the fixed frequency mode, and to hold an enable position over a plurality of transmission cycles in the frequency-hopping mode, wherein the power amplifier power switch in the disable position disables the RF power amplifier, and wherein the power amplifier power switch in the enable position enables the RF power amplifier.

20. The dual-mode apparatus of claim 19, further comprising a control line connected between the TX path, RX/TX mode, and power amplifier power switches and a dual-mode transceiver, wherein the control line allows the dual-mode transceiver to control the positions of the TX path, RX/TX mode, and power amplifier power switches.