Multi-standard transceiver for supporting wireless communications in 2.3-2.4 GHz band

• US 20050254561A1
• Filed: 11/01/2004
• Published: 11/17/2005
• Est. Priority Date: 05/12/2004
• Status: Active Grant

• Current Assignee: Korea Electronics Technology Institute (Government of South Korea)
• Original Assignee: Korea Electronics Technology Institute (Government of South Korea)
• Inventors: Won, Kwang-Ho, Park, Yong Kuk, Seo, Hae-Moon, Yoo, June-Jae
• Granted Patent: US 7,526,018 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

Disclosed herein is a multi-standard transceiver for supporting a plurality of time division deplexing wireless communication standards. The multi-standard transceiver has a Multi-Mode Modem (MMM), a frequency synthesizing unit, a transmission unit, a reception unit and a transmission/reception switch. The MMM selects a transmission standard and a transmission channel and performs digital modulation/demodulation. The frequency synthesizing unit variably adjusts a carrier frequency. The transmission unit receives a digital modulated signal, low-pass-filters the digital modulated signal with a bandwidth thereof variably adjusted according to the selected transmission standard, and up-converts the filtered digital modulated signal into an RF modulated signal. The reception unit down-converts the RF modulated signal, low-pass-filters the down-converted RF modulated signal with a bandwidth thereof being variably adjusted according to the selected transmission standard, and converts the filtered, down-converted RF modulated signal into a digital modulated signal.

Claims

1. A multi-standard transceiver for supporting a plurality of Time Division Duplexing (TDD) wireless communication standards, comprising:

a Multi-Mode Modem (MMM) for selecting a transmission standard and a transmission channel from the plurality of standards, and performing digital modulation/demodulation in a BaseBand (BB) according to the selected transmission standard;

a frequency synthesizing unit for variably adjusting a carrier frequency according to the transmission channel selected by the MMM, and outputting the carrier frequency;

a transmission unit for receiving a digital modulated signal output from the MMM, converting the digital modulated signal into a BB analog modulated signal, low-pass-filtering the analog modulated signal with a bandwidth thereof variably adjusted according to the selected transmission standard, and up-converting the analog modulated signal into a Radio Frequency (RF) modulated signal corresponding to the selected transmission channel, using the carrier frequency;

a reception unit for down-converting a received RF modulated signal to a BB analog modulated signal using the carrier frequency, low-pass-filtering the analog modulated signal with a bandwidth thereof being variably adjusted according to the selected transmission standard, and converting the filtered, analog modulated signal into a digital modulated signal; and

a transmission/reception switch for outputting the RF modulated signal, input from the transmission unit, to an antenna, or outputting the RF modulated signal, received from the antenna, to the reception unit.

2. The multi-standard transceiver as set forth in claim 1, wherein the plurality of wireless communication standards include at least one of IEEE 802.11b and IEEE 802.11g in 2.4 GHz band, and a portable Internet standard in 2.3 GHz band.

3. The multi-standard transceiver as set forth in claim 1, wherein the portable Internet standard in 2.3 GHz band is High-speed Portable Internet (HPi).

4. The multi-standard transceiver as set forth in claim 1, wherein the transmission unit comprises:

a programmable Digital-Analog Converter (DAC) for converting the digital modulated signal, generated by the MMM, into the analog modulated signal with bit resolution thereof being variably adjusted according the transmission standard;

a waveform shaper for low-pass-filtering the analog modulated signal, output from the programmable DAC, with a bandwidth thereof being variably adjusted according the selected transmission standard;

a frequency up converter for up-converting the analog modulated signal, output from the waveform shaper, into an RF modulated signal corresponding to the selected transmission channel using the carrier frequency output from the frequency synthesizer; and

a wideband power amplifier for amplifying the up-converted RF modulated signal.

5. The multi-standard transceiver as set forth in claim 4, further comprising a Direct Current (DC) corrector for correcting a DC component of the analog modulated signal output from the programmable DAC.

6. The multi-standard transceiver as set forth in claim 1, wherein the reception unit comprises:

a wideband low noise amplifier for low-noise-amplifying the RF modulated signal output from the transmission/reception switch;

a frequency down converter for down-converting the RF modulated signal, output from the wideband low noise amplifier, into the analog modulated signal using the carrier frequency output from the frequency synthesizer;

an analog channel selector for low-pass-filtering the analog modulated signal, output from the frequency down converter, with a bandwidth being variably adjusted according to the selected transmission standard; and

a programmable Analog-Digital Converter (ADC) for converting the analog modulated signal, output from the analog channel selector, into the digital modulated signal with bit resolution thereof being variably adjusted in accordance with the selected transmission standard.

7. The multi-standard transceiver as set forth in claim 6, wherein the analog channel selector comprises:

a programmable low-pass filter for low-pass-filtering the down-converted, analog modulated signal with a bandwidth thereof being variably adjusted to the selected transmission standard; and

a programmable amplifier for variably amplifying the analog modulated signal, filtered by the programmable low-pass filter, according to the selected transmission standard.

8. The multi-standard transceiver as set forth in claim 6, wherein the reception unit further comprises a received signal intensity indicator for calculating a strength of the analog modulated signal filtered by the analog channel selector and providing the calculated strength of the filtered analog modulated signal to the channel selector.

9. The multi-standard transceiver as set forth in claim 6, wherein the programmable ADC comprises:

a sigma-delta ADC for converting the analog modulated signal filtered by the analog channel selector, into the digital modulated signal; and

a digital filter for filtering the digital modulated signal, output from the sigma-delta ADC, into a channel bandwidth corresponding to the selected transmission standard.

10. The multi-standard transceiver as set forth in claim 6, wherein the programmable ADC comprises:

a programmable over-sampling analog-digital converter for over-sampling and converting the analog modulated signal, filtered by the analog channel selector, into the digital modulated signal; and

a digital filter for filtering the digital modulated signal, output from the over-sampling ADC, into a channel bandwidth corresponding to the selected transmission standard.

11. The multi-standard transceiver as set forth in claim 6, wherein the programmable ADC comprises:

a programmable ADC for under-sampling and converting the analog modulated signal, filtered by the analog channel selector, according to the selected transmission standard; and

a digital filter for filtering the digital modulated signal, output from the programmable under-sampling ADC, into a channel bandwidth corresponding to the selected transmission standard.

12. The multi-standard transceiver as set forth in claim 1, further comprising an intelligent channel selection block for selecting a channel based on received signal strengths and offsets of channels.

13. The multi-standard transceiver as set forth in claim 1, wherein the frequency synthesizing unit comprises:

an oscillator for generating a local frequency in an RF band;

a programmable divider for variably dividing the local frequency according to the selected transmission standard;

a Digitally Compensated Crystal Oscillator (DCXO) for generating a reference frequency according to the selected transmission standard; and

a frequency synthesizer for converting the frequency, output from the programmable divider, into the carrier frequency corresponding to the selected transmission channel using the reference frequency, and outputting the carrier frequency.

14. A multi-mode RF frequency front-end device for supporting a plurality of TDD wireless communication standards, and performing RF modulation/demodulation according to transmission standard and channel selected from the plurality of TDD wireless communication standards, comprising:

a frequency synthesizing unit for variably adjusting a carrier frequency according to the selected transmission channel, and outputting the carrier frequency;

a transmission unit for receiving a digital modulated signal, converting the digital modulated signal into a BB analog signal, low-pass-filtering the analog modulated signal with a bandwidth thereof variably adjusted according to the selected transmission standard, and up-converting the analog modulated signal into a Radio Frequency (RF) modulated signal corresponding to the selected transmission channel, using the carrier frequency;

a reception unit for down-converting a received RF modulated signal to an BB analog modulated signal using the carrier frequency, low-pass-filtering the analog modulated signal with a bandwidth thereof being variably adjusted according to the selected transmission standard, and converting the filtered, analog modulated signal into a digital modulated signal; and

a transmission/reception switch for outputting the RF modulated signal, input from the transmission unit, to an antenna, or outputting the RF modulated signal, received from the antenna, to the reception unit.

15. The multi-mode RF frequency front-end device as set forth in claim 14, wherein the plurality of wireless communication standards include at least one of IEEE 802.11b and IEEE 802.11g in 2.4 GHz band, and a portable Internet standard in 2.3 GHz band.

16. The multi-mode RF frequency front-end device as set forth in claim 15, wherein the portable Internet standard in 2.3 GHz band is HPi.

17. The multi-mode RF frequency front-end device as set forth in claim 14, wherein the transmission unit comprises:

a programmable DAC for converting the digital modulated signal, generated by the MMM, into the analog modulated signal with bit resolution thereof being variably adjusted according the transmission standard;

a waveform shaper for low-pass-filtering the analog modulated signal, output from the programmable DAC, with a bandwidth thereof being variably adjusted according the selected transmission standard;

a frequency up converter for up-converting the analog modulated signal, output from the waveform shaper, into an RF modulated signal corresponding to the selected transmission channel using the carrier frequency output from the frequency synthesizer; and

a wideband power amplifier for amplifying the up-converted RF modulated signal.

18. The multi-mode RF frequency front-end device as set forth in claim 17, further comprising a DC corrector for correcting a DC component of the analog modulated signal output from the programmable DAC.

19. The multi-mode RF frequency front-end device as set forth in claim 14, wherein the reception unit comprises:

a wideband low noise amplifier for low-noise-amplifying the RF modulated signal output from the transmission/reception switch;

a frequency down converter for down-converting the RF modulated signal, output from the wideband low noise amplifier, into the analog modulated signal using the carrier frequency output from the frequency synthesizer;

an analog channel selector for low-pass filtering the analog modulated signal, output from the frequency down converter, with a bandwidth being variably adjusted according to the selected transmission standard; and

a programmable ADC for converting the analog modulated signal, output from the analog channel selector, into the digital modulated signal with bit resolution thereof being variably adjusted in accordance with the selected transmission standard.

20. The multi-mode RF frequency front-end device as set forth in claim 19, wherein the analog channel selector comprises:

a programmable low-pass filter for low-pass-filtering the down-converted, analog modulated signal with a bandwidth thereof being variably adjusted to the selected transmission standard; and

a programmable amplifier for variably amplifying the analog modulated signal, filtered by the programmable low-pass filter, according to the selected transmission standard.

21. The multi-mode RF frequency front-end device as set forth in claim 14, wherein the frequency synthesizing unit comprises:

an oscillator for generating a local frequency in an RF band;

a programmable divider for variably diminishing the local frequency according to the selected transmission standard;

a DCXO for generating a reference frequency according to the selected transmission standard; and

a frequency synthesizer for converting the frequency, output from the programmable divider, into a carrier frequency corresponding to the selected transmission channel using the reference frequency, and outputting the carrier frequency.