US5233628A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Computer-based bit error simulation for digital wireless communications
Assignee: Virginia Tech Intellectual Properties Inc
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Filing: 1991-05-29
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Granted: 1993-08-03
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Expires: 2011-05-29
Abstract
Abstract A communications stimulation system allows a user to perform a quantitative or subjective test of digital baseband devices over wireless channels using actual measured or modeled propagation data. The digital wireless communication simulation system is capable of simulating the transient nature of channels and radio hardware so that loss of synchronization can be included in the simulation. The simulator is a combination of computer software and hardware that computes a convolution, in the time domain, of a sequence of binary digits or data symbols (i.e., the data stream) with a computer model of a radio transmitter, a propagation channel or channels and a receiver. The transmitter typically comprises a coder, a pulse shaper, a modulator, and a spreader. The propagation channel or channels may include impulsive and average noise levels, co-channel interference and adjacent interference levels, fading and multipath propagation events, and non-linear channel and radio system effects. The receiver system typically comprises at least a filter bank, a demodulator, a despreader, a synchronizer, a detector, and a decoder. The data stream may either be random or applied by the user. The software computes the bit-by-bit sequence for replay at a later time. Once stored, the bit-by-bit error sequence can be clocked through a hardware data port and compared with an applied data stream in real time. The output of the hardware data port is a real time sequence of bits that has errors due to the bit-by-bit simulation computed earlier by the software.
Inventors
- 👤 Theodore S. Rappaport
- 👤 Victor Fung
- 👤 Michael D. Keitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:00
CPC Classifications
H; H04; H04B; H04B17/00; H04B17/30; H04B17/391; H04B17/3912; H04B17/373
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
108 words
A wireless digital communication system simulation system comprising: storage means for strong data representing computed bit error data; means for accessing said storage means to generate a bit error data stream e k ; means for inputting a data stream d k representing a data stream output of digital communication system; means responsive to said accessing means for combining said bit error data stream e k and said data stream d k and simulating operation of the digital communication system including a fading channel and interference signals and generating a data stream d' k ; and means for receiving data representing said data stream d' k for analysis.
Claim 2
Dependent Claim
108 words
A wireless digital communication system simulation system comprising: storage means for strong data representing computed bit error data; means for accessing said storage means to generate a bit error data stream e k ; means for inputting a data stream d k representing a data stream output of digital communication system; means responsive to said accessing means for combining said bit error data stream e k and said data stream d k and simulating operation of the digital communication system including a fading channel and interference signals and generating a data stream d' k ; and means for receiving data representing said data stream d' k for analysis.
Claim 3
Dependent Claim
63 words
The wireless digital communication system simulation system recited in claim 1 wherein said means for accessing said storage means to generate said data error stream e k comprises: means for addressing said storage means to read out said data representing said computed bit error data; and shift register means for converting said read out data to said data error stream e k .
Claim 4
Dependent Claim
120 words
The wireless digital communication system simulation system recited in claim 2 further comprising: means for entering system parameters including modulation type, data rate and channel type; means for accessing said system parameters and simulating a communications channel to generate impulse response data of the communications channel; means for generating a predetermined number of pseudorandom symbols and performing signal mapping according to the modulation type to generate a first output; means for convolving said first output with said impulse response to said communications channel to generate a second output; means for adding noise to said second output; and means for detecting said second output and determining a number of bit errors to generate said stored data representing computed bit error data.
Claim 5
Dependent Claim
93 words
The wireless digital communication system simulation system recited in claim 3 further comprising: means for storing data of an impulse response of a first and second filters used for communication systems; means for convolving said first output with said impulse response to said first filter to generate an output which is convolve with said impulse response data of said communications channel to generate said second output; and means for convolving said second output with noise added with said impulse response of said second filter to generate said third output representing a received signal.
Claim 6
Dependent Claim
28 words
The wireless digital communication system simulation system recited in claim 4 further comprising means for generating co-channel interference before simulating said communication channel to generate its impulse response.
Claim 7
Dependent Claim
47 words
The wireless digital communication system simulation system recited in claim 1 wherein said means for combining said bit error data stream e d and said data stream d k performs an Exclusive OR function on said data streams to generate bit-by-bit said data stream d' k .
Claim 8
Dependent Claim
119 words
A process for simulating a wireless digital communication system on a programmed digital computer comprising the steps of: entering system parameters including modulation type, data rate, multiple access technique, and channel type; accessing said system parameters and situating a communications channel to generate impulse response data of the communications channel; generating a predetermined number of pseudorandom symbols and performing signal mapping according to the modulation type to generate a first output; convolving said first output with said impulse response to said communications channel to generate a second output; adding noise to said second output; and detecting said second output and generating data representing computed bit error data from which a bit error data stream e k may be generated.
Claim 9
Dependent Claim
119 words
A process for simulating a wireless digital communication system on a programmed digital computer comprising the steps of: entering system parameters including modulation type, data rate, multiple access technique, and channel type; accessing said system parameters and situating a communications channel to generate impulse response data of the communications channel; generating a predetermined number of pseudorandom symbols and performing signal mapping according to the modulation type to generate a first output; convolving said first output with said impulse response to said communications channel to generate a second output; adding noise to said second output; and detecting said second output and generating data representing computed bit error data from which a bit error data stream e k may be generated.
Claim 10
Dependent Claim
94 words
The process for simulating a wireless digital communication system recited in claim 7 further comprising the steps of: generating a bit error data stream e k from said data representing computed bit error data; and combining said bit error data stream e k and a data stream d k representing a data stream output of a wireless digital communication system to simulate operation of the wireless digital communication system including a fading channel and generating a data stream d' k as a result of combining said data streams e k and d k .
Claim 11
Dependent Claim
24 words
The process for simulating a wireless digital communication system recited in claim 8 further comprising the step of determining a number of bit errors.
Claim 12
Dependent Claim
66 words
The process for simulating a wireless digital communication system recited in claim 9 wherein said step of determining a number of bit errors comprises the steps of: comparing the data representing said data streams d k and d' k to determine a bit error rate for said digital communication system including the fading channel; and determining an average bit error rate for a simulated received signal.
Claim 13
Dependent Claim
87 words
The process for simulating a wireless communications system recited in claim 7, further comprising the steps of: storing data of an impulse response of a first an second filters; convolving said first output with said impulse response of said first filter to generate an output which is convolved with said impulse response data of said communications channel to generate said second output; and convolving said second output with noise added with said impulse response to said second filter to generate said third output representing a received signal.
Claim 14
Dependent Claim
30 words
The process of simulating a wireless communications system recited in claim 11 further comprising the step of generating co-channel interference before simulating said communication channel to generate its impulse response.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-02 | 1997-02-01 | 1997-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-02 | 2001-02-01 | 2001-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-02 | 2005-02-01 | 2005-08-03 | $7700.00 | Window Closed / Lapsed |