US6580705B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal combining scheme for wireless transmission systems having multiple modulation schemes
Assignee: Nokia of America Corp
•
Filing: 1999-10-28
•
Granted: 2003-06-17
•
Expires: 2019-10-28
Abstract
Abstract In a wireless transmission system that transmits the same information in parallel using two or more different types of modulation schemes, such as a satellite-based digital audio transmission system transmitting two TDM signals and a single OFDM signal, a receiver processes the differently modulated signals to generate separate demodulated signals that are then combined to form a single combined signal for further processing (e.g., decoding). In one embodiment, the receiver applies a maximal ratio combining (MRC) technique to generate a single optimal ratio combined signal from the differently modulated signals. By combining the differently modulated signals using an MRC technique, the adverse affects of noise related to inter-symbol interference in the individual signals can be reduced and the complexity of hardware in the receiver can be reduced.
Inventors
- 👤 Habib Riazi
- 👤 Zulfiquar Sayeed
- 👤 Dunmin Zheng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:08
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/26; H04L27/2601; H04L1/00; H04L1/02; H04L1/06
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
103 words
A transmitter, comprising: (a) an encoder to add redundancy to a data sequence; (b) an interleaver connected to the encoder to output encoded symbols as interleaved symbols in data frames; (c) an inserter connected to the interleaver to insert synch bits into data frames to generate synchronized data, of which copies of the synchronized data undergo further processing; (d) a first modulator for modulating a first copy of the synchronized data to generate a signal having a first modulation scheme; and (e) a second modulator for modulating a second copy of the synchronized data to generate a signal having a second modulation scheme.
Claim 2
Dependent Claim
103 words
A transmitter, comprising: (a) an encoder to add redundancy to a data sequence; (b) an interleaver connected to the encoder to output encoded symbols as interleaved symbols in data frames; (c) an inserter connected to the interleaver to insert synch bits into data frames to generate synchronized data, of which copies of the synchronized data undergo further processing; (d) a first modulator for modulating a first copy of the synchronized data to generate a signal having a first modulation scheme; and (e) a second modulator for modulating a second copy of the synchronized data to generate a signal having a second modulation scheme.
Claim 3
Dependent Claim
21 words
The transmitter of claim 1 , wherein: the first modulator is a DQSPK modulator and the first modulation scheme is OFDM.
Claim 4
Dependent Claim
21 words
The transmitter of claim 1 , wherein: the second modulator is a QSPK modulator and the second modulation scheme is TDM.
Claim 5
Dependent Claim
31 words
The transmitter of claim 1 , further comprising a third modulator for modulating a third copy of the synchronized data to a generate a time-delayed signal having a third modulation scheme.
Claim 6
Dependent Claim
41 words
The transmitter of claim 4 , wherein: the third modulator is a DQSPK modulator and the third modulation scheme is TDM, wherein the time-delayed signal is delayed by a delay buffer configured with the third modulator to a known delay value.
Claim 7
Dependent Claim
28 words
The transmitter of claim 1 , wherein: the first modulator is adapted to generate an OFDM signal; and the second modulator is adapted to generate a TDM signal.
Claim 8
Dependent Claim
27 words
The transmitter of claim 6 , wherein: the first modulator performs DQPSK modulation followed by a differential modulation over frequency; and the second modulator performs QPSK modulation.
Claim 9
Dependent Claim
30 words
The transmitter of claim 1 , further comprising a third modulator for modulating a third copy of the synchronized data to a generate a signal having a third modulation scheme.
Claim 10
Dependent Claim
39 words
The transmitter of claim 8 , wherein: the first modulator is adapted to generate an OFDM signal; the second modulator is adapted to generate a first TDM signal; the third modulator is adapted to generate a second TDM signal.
Claim 11
Dependent Claim
23 words
The transmitter of claim 9 , wherein the OFDM signal and the second TDM signal are time-delayed relative to the first TDM signal.
Claim 12
Dependent Claim
87 words
The transmitter of claim 10 , wherein: the first modulator comprises a delay buffer followed by a DQPSK modulator followed by a frequency interleaver and difference modulator, followed by an inverse fast Fourier transform (IFFT), followed by a guard interval block; the second modulator comprises a QPSK modulator followed by an equalizer training sequence inserter followed by an intermediate frequency (IF) modulator; and the third modulator comprises a delay buffer followed by a QPSK modulator followed by an equalizer training sequence inserter followed by an IF modulator.
Claim 13
Dependent Claim
33 words
The transmitter of claim 9 , wherein: the first modulator performs DQPSK modulation followed by a differential modulation over frequency; the second modulator performs QPSK modulation; and the third modulator performs QPSK modulation.
Claim 14
Dependent Claim
93 words
A transmitter, comprising: (a) an encoder adapted to encode input data; (b) an interleaver adapted to generate interleaved data from encoded data generated by the encoder; (c) an inserter adapted to insert synch bits into the interleaved data to generate synchronized data; (d) a first modulator adapted to modulate a first copy of the synchronized data using a first modulation scheme to generate a first modulated signal; and (e) a second modulator adapted to modulate a second copy of the synchronized data using a second modulation scheme to generate a second modulated signal.
Claim 15
Dependent Claim
93 words
A transmitter, comprising: (a) an encoder adapted to encode input data; (b) an interleaver adapted to generate interleaved data from encoded data generated by the encoder; (c) an inserter adapted to insert synch bits into the interleaved data to generate synchronized data; (d) a first modulator adapted to modulate a first copy of the synchronized data using a first modulation scheme to generate a first modulated signal; and (e) a second modulator adapted to modulate a second copy of the synchronized data using a second modulation scheme to generate a second modulated signal.
Claim 16
Dependent Claim
28 words
The transmitter of claim 13 , wherein: the first modulator is adapted to generate an OFDM signal; and the second modulator is adapted to generate a TDM signal.
Claim 17
Dependent Claim
27 words
The transmitter of claim 14 , wherein: the first modulator performs DQPSK modulation followed by a differential modulation over frequency; and the second modulator performs QPSK modulation.
Claim 18
Dependent Claim
30 words
The transmitter of claim 13 , further comprising a third modulator for modulating a third copy of the synchronized data to a generate a signal having a third modulation scheme.
Claim 19
Dependent Claim
39 words
The transmitter of claim 16 , wherein: the first modulator is adapted to generate an OFDM signal; the second modulator is adapted to generate a first TDM signal; the third modulator is adapted to generate a second TDM signal.
Claim 20
Dependent Claim
23 words
The transmitter of claim 17 , wherein the OFDM signal and the second TDM signal are time-delayed relative to the first TDM signal.
Claim 21
Dependent Claim
87 words
The transmitter of claim 18 , wherein: the first modulator comprises a delay buffer followed by a DQPSK modulator followed by a frequency interleaver and difference modulator, followed by an inverse fast Fourier transform (IFFT), followed by a guard interval block; the second modulator comprises a QPSK modulator followed by an equalizer training sequence inserter followed by an intermediate frequency (IF) modulator; and the third modulator comprises a delay buffer followed by a QPSK modulator followed by an equalizer training sequence inserter followed by an IF modulator.
Claim 22
Dependent Claim
33 words
The transmitter of claim 17 , wherein: the first modulator performs DQPSK modulation followed by a differential modulation over frequency; the second modulator performs QPSK modulation; and the third modulator performs QPSK modulation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2006-06-16 | 2006-12-16 | 2007-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-06-16 | 2010-12-16 | 2011-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-06-16 | 2014-12-16 | 2015-06-17 | $7700.00 | Window Closed / Lapsed |