Processing architecture for a receiving system with improved directivity and signal to noise ratio

• US 7,457,603 B2
• Filed: 06/06/2005
• Issued: 11/25/2008
• Est. Priority Date: 12/03/1998
• Status: Expired due to Fees

• Current Assignee: Callahan Cellular LLC (Intellectual Ventures LLC)
• Original Assignee: Apex/Eclipse Systems, Inc.
• Inventors: Smith, Harry B.
• Primary Examiner(s): Gesesse; Tilahun B
• Application Number:
  US11/145,216
• Publication Number:
  US 20060079192A1
• Time in Patent Office: 1,268 Days
• Field of Search: 455/562.1, 455/561, 455/560, 455/277.1, 455/277.2, 455/278.1, 455/276.1, 455/272, 455/296, 455/283, 375/347, 375/231, 379/343
• US Class Current: 455/278.1
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]

Abstract

A receive system providing enhanced directivity in the form of a narrowed receive beam and a relatively small antenna with performance comparable to a much larger antenna at similar frequencies. Received signals are converted to digital values and stored in a manner which enables subsequent processing directed to improving the resolution of the received signals and to reduce the associated noise corresponding to the received data samples. The Signal-to-Noise ratio of the received data signals is improved as a result of processing techniques made possible by the configuration of the antenna and the digitally stored nature of the received data.

Claims

1. A process for substantially improving the signal to noise ratio of a receive system, said process comprising the step of:

iteratively converging on an estimate of a noise-only portion of received signals plus noise for both in-phase and quadrature components of said received signals plus noise;

obtaining said noise-only estimates from a net algebraic sum of a series of iterations which provides close approximations to the magnitude of the noise for each trial;

sensing a change in polarity associated with the noise-only portion of the received signals plus noise for respective trials; and

reducing the actual noise of said received signals plus noise by subtracting said close approximations from said received signals plus noise.

2. The process for substantially improving the signal to noise ratio of a receive system claimed in claim 1, said process further comprising the steps of:

storing selected signal plus noise data;

comparing said noise-only estimates of each iteration of each trial from each group and using a result of said comparison to remove most of the noise from each signal plus noise value that was stored in said storing and delaying steps.

3. The process claimed in claim 2, wherein the signal plus noise is sampled at a carrier rate equal to the frequency of a carrier signal and the iterative process is conducted at a second rate to achieve non real-time performance.

4. The process claimed in claim 3, wherein a bandwidth and a signal handling capability of said receive system are not adversely compromised but rather the process results in a known delay from real time, wherein the predetermined delay is dependent upon the selection of an appropriate processing speed and the fixed delay time is utilized as a processing time to improve the signal-to-noise ratio of said system.

5. A method according to claim 4 further comprising iterative probing with bipolar sensing conducted in non-real-time to improve the entropy of the receive system.

6. An iterative method of improving the signal to noise ratio in a receive signal, the method comprising:

sampling the receive signal for at least two successive samples having the same phase reference using an analog to digital converter, wherein a system clock controls the timing of the sampling;

establishing an array of signal-plus-noise values derived from the two successive samples;

algebraically adding predetermined successive digital values to the signal-plus-noise values of the array; and

assigning the predetermined successive digital values added to the array elements as either signal values or noise values during different iterations of the method wherein the signal does not alter the noise and the noise does not alter the signal.

7. A computer readable medium programmed to carry out the method of claim 6.

8. A system comprising:

means for iteratively converging on an estimate of a noise-only portion of received signals plus noise for both in-phase and quadrature components of said received signals plus noise;

means for obtaining said noise-only estimates from a net algebraic sum of a series of iterations which provides close approximations to the magnitude of the noise for each trial;

means for sensing a change in polarity associated with the noise-only portion of the received signals plus noise for respective trials; and

means for reducing the actual noise of said received signals plus noise by subtracting said close approximations from said received signals plus noise.

9. A system for transmitting and receiving communication signal the system comprising:

a single antenna including an array of elements each operable to receive the communication signal, wherein the communication signal includes a signal component and a noise component;

a matrix generator operable to generate a matrix including respective values of the communication signal from the elements of said antenna;

an injector unit operable to incrementally add a predetermined sequence of values to each of the matrix values;

a polarity change sensor operable determine a particular value of the predetermined sequence of values which resulted in the noise component of the respective communication signal to change polarity when the particular value is added to the respective communication signal;

a noise reducer operable to determine an estimate of the noise component of the communication signal based on the particular value determined by said polarity change sensor and subtract that estimate from the communication signal.

10. The system claimed in claim 9, further comprising:

an antenna resolution unit operable to process the noise reduced communication signal from said noise reducer to improve the resolution of said antenna.