Sharp Corporation

Teknekron Communications Systems, Inc.

Atmel Corporation

Tcsi Corporation

Teknekron Communication Systems, Inc.

Jong-Keung Cheng

Nan-Sheng Lin

Mihran H Touriguian

Robert Kavaler

Tony S Lee

Amine Haoui

Ravi Subramanian

Kenkichi Suzuki

Biswa Ghosh

In accordance with IS-136 standard, an analog wireless signal and a digitally encoded wireless signal can be received by a remote telecommunicating device. The remote device can differentiate between the analog wireless signal and the digitally encoded wireless signal by measuring the average energy of the signal in the portion of the baseband signal that is expected to contain the Supervisory Audio Tone signal, and the portion of the baseband signal that is expected to be outside of the audio band for an analog signal. The average energy of the portion outside of the audio band is subtracted from the average energy of the SAT signal. The difference is compared to a threshold, and based upon the comparison, the characteristic of the received wireless signal, i.e. analog or digital, is determined.

Method and apparatus for differentiating a wireless analog signal from a

A digital wireless communication system operates between a first unit and a second unit. The received digitally encoded signal is sampled to produce a first sampled digital signal. A first bank of match filters with each match filter having a different frequency range is used to pass the first sampled digital signal therethrough. The output of the first bank of match filters having the largest amplitude is selected along with the match filter which produced the largest amplitude output. The digitally encoded signal having this 'coarse' frequency range is then passed through a second bank of match filters. Each of the match filters has a fine frequency different from one another. The output of the second bank of match filters is produced and the output having the largest amplitude is selected. In addition, the filter producing the largest amplitude from the second bank of match filters is also selected.

Method and apparatus to determine the frequency and time slot position

In a digital wireless communication system communicating between a mobile unit and a stationary unit, a received digitally encoded signal is sampled to produce a first sampled digital signal having a plurality of symbols. The short term energy over a plurality of a contiguous symbols is measured. The short term energy symbol over a first plurality of a contiguous short term energy points is measured. The short term energy average over a second plurality of contiguous short term energy points is measured. The second plurality of contiguous short term energy points is spaced apart from the first plurality of contiguous short term energy points. The difference between the first short term energy average and the second short term energy average is calculated to derive an estimate of the speed of the mobile unit relative to the base unit.

Method of estimating the speed of a mobile unit in a digital wireless

An equalization method for digitally encoded signals transmitted in a plurality of non-contiguous time slots has a digitally encoded synchronization signal commencing in each time slot followed by a digitally encoded data signal having a digitally encoded marker signal at a predetermined time period. The synchronization signal of the assigned time slot ('first synchronization signal') and the digitally encoded data signal of the assigned time slot including the marker signal, and the digitally encoded synchronization signal of the immediately succeeding non-assigned time slot ('second synchronization signal') are all stored. The location of the minimum energy point of the stored digitally encoded signals is determined. Equalization is performed starting from the first synchronization signal to the minimum energy point. Then, the equalization commences from the second synchronization signal backwards until the minimum energy point is reached.

Method of equalizing digitally encoded signals transmitted in a

In a digital wireless communication system, a first unit transmits a digitally encoded signal to a second unit in a plurality of non-contiguous time slots. Within each time slot, the digitally encoded signal has a synchronization signal portion followed by a data signal portion. The second unit has an antenna to receive the synchronization signal portion of the digitally encoded signal. The second unit also has a clock to generate a clock signal at a first rate having a sampling phase. An analog to digital converter receives the clock signal and the synchronization signal and samples the synchronization signal at the first rate to generate a first plurality of symbols. An interpolator receives the first plurality of symbols and interpolates the first plurality of symbols to generate a second plurality of symbols at a second rate. The second rate is a multiple of the first rate. A match filter receives the second plurality of symbols and compares the second plurality symbol of symbols to a stored plurality of symbols to generate an error signal. The sampling phase of the clock signal is altered in response to the error signal, after to the receipt of the synchronization signal.

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Danville, CA, United States of America

Jong-Keung Cheng