CN1423423A - System and method for improving high data rate wireless terminal characteristic using diversity - Google Patents

Abstract

A system and method for improving performance in HDR (High Data Rate) wireless terminals utilizing diversity techniques is disclosed. The wireless terminal includes: two transmit paths, one containing a duplexer and the other bypassing the duplexer; and two receive paths, one containing a duplexer and the other not containing a duplexer and completely isolated from any transmit path . When the terminal is determined to be in HDR mode, both the transmit path including the duplexer and both receive paths are used. When the terminal is operating in a low data rate mode, the use of a transmit path that bypasses the duplexer and a receive path completely isolated from the transmit path results in a lower minimum detectable signal, thus reducing current consumption in the wireless terminal.

Description

Systems and methods for improving performance of high data rate wireless terminals using diversity

Technical field

The present invention generally relates to an antenna diversity technique in a wireless terminal, and more particularly, to a technique for improving transmission and reception of a high data rate wireless terminal.

technical background

In a conventional wireless terminal, the transmitter and receiver share an antenna. When a reception antenna diversity technique is applied to a wireless terminal, multiple antennas are provided to selectively combine high-quality signals, thereby improving reception efficiency and increasing a data processing rate. FIG. 1 is a schematic diagram showing a system for performing antenna diversity in a conventional wireless terminal. Referring to FIG. 1, a receiver Rx connected to a switch SW1 detects the strength of a signal received through a specific antenna of ANT1 or ANT2. If the signal strength detected by a particular antenna is above a predetermined threshold, the receiver Rx utilizes that particular antenna. If the detected signal strength is below the predetermined threshold, the receiver utilizes the other antenna by switching SW1 to the other antenna. After the receiver selects an antenna, the transmitter Tx utilizes the remaining antennas.

In addition, a conventional wireless terminal isolates a transmission signal from a reception signal through a duplexer, and performs voice and data services through a transmitter circuit and a receiver circuit. FIG. 2 is a schematic diagram of a conventional wireless terminal isolating a sending signal and a receiving signal through a duplexer. Referring to FIG. 2, a duplexer 200 interposed between an antenna and a transmitter Tx isolates a transmission signal and a reception signal so as to perform a full duplex operation. That is, during transmission, the output power of the PAM (Power Amplification Module) in the transmitter Tx (not shown) is transmitted to the antenna ANT with the maximum power through the duplexer. During reception, a low power RF signal is received through the antenna ANT and transmitted through a duplexer to a low noise amplifier (not shown) in the receiver Rx for reception at maximum power. However, there is high insertion loss when transmitting and receiving signals at maximum power. Also, due to the imperfect isolation of the individual signals passing through the duplexer, there is interference between the transmitted signal and the received signal. This interference occurs because the transmitted power is usually much higher than the received power and thus interferes with the receiver.

The disadvantage of conventional wireless terminals is that when the transceiver utilizes a single antenna and duplexer as the common path, the losses of the duplexer device itself and the incomplete isolation between the transmitter and receiver increase the minimum detectable signal (MDS) level, resulting in an increase in the current consumption of the wireless terminal.

Therefore, there is a need to completely isolate the transmit path from the receive path during low data rate processing mode and avoid wireless terminals using duplexers, thus making it possible to reduce the level of the minimum detectable signal and the current consumption of the wireless terminal.

Contents of invention

Accordingly, an object of the present invention is to improve transmission and reception performance of a wireless terminal during low-rate data processing in an HDR (High Data Rate) transmission system.

Another object of the present invention is to provide a radio terminal in which the transmit path is completely isolated from the receive path during the low data rate processing mode and avoids the use of duplexers, thus making it possible to reduce the level of the minimum detectable signal and the current of the radiotelephone consume.

Another object of the present invention is to provide a wireless terminal utilizing a first receive path, a second receive path and a transmit path during a high data rate processing mode.

In order to achieve the above and other objects, a wireless terminal is provided, which includes: a first receiver for sending and receiving general signals such as voice transmission, the receiver includes: a first antenna, a A first receive path through the duplexer, a first transmit path through the duplexer, a second transmit path bypassing the duplexer, and a transmit switch for switching between the first and second transmit paths. The wireless terminal also includes a second receiver for receiving high rate data, the receiver including: a second antenna and a second receive path. Since the second receiver does not perform transmission, it is not connected to the duplexer.

A method for achieving the above and other objects using the above system is also provided. If it is determined that HDR transmission is occurring, the transmit switch is set to utilize the first transmit path in the first receiver. The incoming signal is then received by using the first and second receive paths in common. If no HDR transmission is detected, the transmit switch is set to use the second transmit path bypassing the duplexer in the first receiver. The incoming signal is then received using only the second path in the second receiver. By completely isolating the transmit path from the receive path and avoiding the use of duplexers during low data rate processing modes, the minimum detectable signal level can be reduced and the current consumption of the radiotelephone can also be reduced.

Description of drawings

From the following detailed description in conjunction with the accompanying drawings, the above-mentioned and other various objects, features and advantages of the present invention will become more clear, wherein:

FIG. 1 is a schematic diagram showing a system for performing antenna diversity in a conventional wireless terminal;

FIG. 2 is a schematic diagram showing a conventional wireless terminal that isolates transmission signals and reception signals through a duplexer;

Figure 3 is a schematic diagram of an HDR wireless terminal according to a preferred embodiment of the present invention; and

FIG. 4 is a flowchart illustrating the method of operation of the preferred embodiment of FIG. 3 .

Detailed ways

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention with unnecessary details.

Referring now to the various drawings, wherein like numerals represent like or identical components throughout the several views. Fig. 3 is a schematic diagram of an HDR wireless terminal according to a preferred embodiment of the present invention. Referring to FIG. 3 , the present invention relates to a wireless terminal having multiple antennas (in this example, two antennas), a first receiver (receiver #1) and a second receiver (receiver #2) are respectively connected to the first antenna ANT1 and the second antenna ANT2. Receiver #1 performs signal transmission and reception in the wireless terminal, while receiver #2 is used to receive up to 2.4Mbps high rate (or high speed) data defined by the IS-856 standard, and only performs signal reception. Receiver #2 exclusively performs a well-known 1xEV-D0 (evolution-data only) operation. In order to perform transmission and reception of signals, receiver #1 includes a first transmission path Tx#1, a second transmission path Tx#2, and a reception path Rx#1. Since receiver #2 only performs signal reception, it includes only reception path Rx#2.

First, the structure of receiver #1 of the preferred embodiment will be described. As described above, the receiver #1 includes: a first transmission path Tx#1, a second transmission path Tx#2 and a reception path Rx#1. Except for the duplexer 305, the structures of the transmission paths Tx#1 and Tx#2 are substantially the same. Both Tx#1 and Tx#2 include a multiplier 324 , an RF BPF (Radio Frequency Band Pass Filter) 323 , a driver 322 , a BPF (Band Pass Filter) 321 , and a power amplifier 320 connected in series to the transmission switch 315 . The transmission switch 315 controlled by the microprocessor 310 determines whether Tx#1 or Tx#2 is used according to the position of the transmission switch 315 . To control the position of the transmit switch 315, the microprocessor determines whether the wireless terminal is in a low data rate processing mode or a high data rate processing mode. The transmit switch 315 is switched to position 1 if the wireless terminal is in low data rate processing mode. The transmit switch 315 is switched to position 2 if the microprocessor determines that the wireless terminal is in a high data rate processing mode. When the transmit switch is in position 1, Tx#1 is used and the transmit signal is sent to the antenna ANT1 through the duplexer 305 . In another case, when the transmit switch 315 is in position 2, Tx#2 is used and the transmit signal bypasses the duplexer 305 and is directly transmitted to the antenna ANT1. Reception path #1 of receiver 1 includes antenna ANT1, duplexer 305, LNA (Low Noise Amplifier) 316A, BPF 317A, multiplier 318A, and RF BPF 319A connected in series.

Receiver #2 includes a receiving path Rx#2 whose structure is substantially the same as that of Rx#1 except that the duplexer 305 is not provided. Rx#2 includes antenna ANT2, LNA 316B, BPF 317B, multiplier 318B and RF BPF 319B connected in series for receiving data when the wireless terminal is in low data rate processing mode or in high data rate processing mode.

Generally, an antenna for a wireless terminal includes a helical antenna and a whip antenna protruding outside the wireless terminal. In a preferred embodiment of the invention, although not limiting, these types of antennas are also used. The helical antenna operates when the whip antenna is retracted into the interior of the wireless terminal, and the whip antenna operates when the whip antenna is extended from the wireless terminal.

Table 1 drawn below shows the characteristics of the antennas ANT1 and ANT2.

Table 1 bandwidth type ANT1 Rx/Tx, Broadband Helical Antenna with Whip Antenna ANT2 Rx, narrowband Helical antenna (whip antenna may be used depending on antenna length)

The method of operation of the preferred embodiment will now be described with reference to FIGS. 3 and 4 . Referring to FIG. 4, a flow chart illustrating the method of operation of the preferred embodiment of FIG. 3, in step 401, a voice data service is started. In step 402, the microprocessor 310 determines whether the wireless terminal is operating in a high data rate processing mode or in a low data rate processing mode. If at step 402 the microprocessor 310 determines that the wireless terminal should be operating in a high data rate processing mode, then at step 403 the microprocessor 310 switches the transmit switch 315 to position one. With transmit switch 315 in position 1, transmit path Tx#1 including duplexer 305 will be used for transmission at high data rates. The duplexer 305 is used to isolate the transmit signal along Tx#1 from the receive signal along Rx#1. In step 404, receive path Rx#1 is powered on and used in step 405 together with receive path Rx#2 of receiver #2 to receive signals. Depending on which of the two receive paths is receiving the stronger signal, Rx #1 and Rx #2 are used alternately.

In step 402, if the microprocessor 310 determines that the wireless terminal will not operate in the high data rate processing mode, but in the low data rate processing mode, then in step 406, the transmit switch 315 is switched by the microprocessor 310 to position 2 . With the transmit switch in position 2, the transmit path Tx#2 of the bypass duplexer 305 is used. In step 407, receive path Rx#1 is powered off and the task of receiving signals in step 408 is performed solely by receive path Rx#2 of receiver #2 which is completely isolated from transmit path Tx#2. This results in a lower minimum detectable signal, which enables the wireless terminal to receive lower power signals, thus reducing power consumption.

Table 2 provided below further illustrates the operation of the wireless terminal.

Table 2 model transceiver in use operate Send switch position Diplexer Low Data Rate Processing Mode Rx#2, Tx#2 2 Unused High Data Rate Processing Mode Rx#1 and Rx#2Tx#1 1 In use

As mentioned above, today's wireless terminals have limited performance in low data rate mode processing due to the use of duplexers. However, the present invention completely isolates the transmit path from the receive path during the low data rate processing mode and avoids the use of duplexers, thus making it possible to reduce the minimum detectable signal level and the current consumption of the radiotelephone.

While preferred embodiments of the present invention have been described above, those skilled in the art will understand that changes in form and details may be made without departing from the spirit and scope of the invention as defined by the appended claims. Various changes can be made.

Claims (15)

1. A system for improving performance in HDR (High Data Rate) wireless terminals utilizing diversity techniques, comprising; The first receiver is used for sending and receiving signals, and the receiver includes a first antenna, a first receiving path passing through a duplexer, a first transmitting path passing through the duplexer, and bypassing the duplexer a second transmission path, and a transmission switch for switching between said first and second transmission paths; and The second receiver is used for receiving high-rate data, and the receiver includes a second antenna and a second receiving path. 2. The system for improving performance in HDR (High Data Rate) wireless terminals as claimed in claim 1, wherein the first transmission path comprises: a multiplier for spreading the transmitted signal; RF BPF (Radio Frequency Bandpass Filter); driver; BPF; and A power amplifier for amplifying a transmission signal is connected in series and transmits a transmission signal from the first antenna through a duplexer. 3. The system for improving performance in HDR (High Data Rate) wireless terminals as claimed in claim 1, wherein the second transmission path comprises: a multiplier for spreading the transmitted signal; RF BPF; driver; A power amplifier is connected in series and transmits a transmit signal from the first antenna. 4. The system for improving performance in HDR (High Data Rate) wireless terminals as claimed in claim 1, wherein the first receiving path comprises: A low noise amplifier for amplifying the received signal; BPF; multiplier; and The RF BPF is connected in series and receives the received signal from the first antenna through the duplexer. 5. The system for improving performance in HDR (High Data Rate) wireless terminals as claimed in claim 1, wherein the first receiving path comprises: A low noise amplifier for amplifying the received signal; BPF; multiplier; and an RF BPF connected in series and receiving received signals from said first antenna. 6. The system for improving performance in an HDR (High Data Rate) wireless terminal as claimed in claim 1, further comprising a microprocessor for controlling a transmit switch. 7. The system for improving performance in HDR (High Data Rate) wireless terminals as claimed in claim 1, further comprising a microprocessor for determining whether HDR transmission is occurring. 8. The system for improving performance in HDR (High Data Rate) wireless terminals as claimed in claim 1, wherein the first and second antennas are helical antennas. 9. The system for improving performance in HDR (High Data Rate) wireless terminals as claimed in claim 1, wherein the first antenna is a helical antenna combined with a whip antenna. 10. A method for improving performance in a HDR (High Data Rate) wireless terminal utilizing diversity techniques, the wireless terminal comprising: a first receiver for transmitting and receiving signals, the first receiver comprising a first antenna, A first receive path through a duplexer, a first transmit path through said duplexer, a second transmit path bypassing said duplexer, and a pass between said first and second transmit paths a transmit switch for switching; and a second receiver for receiving high rate data, the second receiver including a second antenna and a second receiver path, the method comprising: Determine if an HDR transfer is occurring; When it is determined that HDR transmission is occurring, setting a transmit switch for use on the first transmit path in the first receiver, and receiving signals by using the first and second receive paths in common; and When it is determined that HDR transmission does not occur, the transmit switch is set to use the second transmit path bypassing the duplexer in the first receiver, and only utilize the second receive path in the second receiver to receive signals. 11. The method of improving performance in a HDR (High Data Rate) wireless terminal as claimed in claim 10, wherein the microprocessor determines whether HDR transmission is taking place. 12. The method for improving performance in an HDR (High Data Rate) wireless terminal as claimed in claim 10, wherein the microprocessor controls setting of the transmit switch. 13. A method for improving performance in a HDR (High Data Rate) wireless terminal using diversity techniques, the wireless terminal comprising: a first receiver for transmitting and receiving signals, the first receiver comprising a first antenna, A first receive path through a duplexer, a first transmit path through said duplexer, a second transmit path bypassing said duplexer, and a pass between said first and second transmit paths a transmit switch for switching; and a second receiver for receiving high rate data, the receiver including a second antenna and a second receiver path, the method comprising: determine if HDR reception is occurring; When it is determined that HDR reception is occurring, setting a transmit switch to use on the first transmit path in the first receiver, and receiving signals by using the first and second receive paths in common; and When it is determined that HDR reception does not occur, the transmit switch is set to use the second transmit path bypassing the duplexer in the first receiver, and only use the second receive path in the second receiver to receive signals. 14. The method of improving performance in a HDR (High Data Rate) wireless terminal as claimed in claim 13, wherein the microprocessor determines whether HDR transmission is taking place. 15. The method for improving performance in an HDR (High Data Rate) wireless terminal as claimed in claim 13, wherein the microprocessor controls the setting of the transmit switch.

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