MIMO-adapted distributed antenna system

• US 7,483,504 B2
• Filed: 02/06/2008
• Issued: 01/27/2009
• Est. Priority Date: 02/12/2007
• Status: Active Grant

• Current Assignee: Corning Optical Communications LLC (Corning Incorporated)
• Original Assignee: Mobileaccess Networks Limited (Corning Incorporated)
• Inventors: Saban, Ofer, Harel, Dror, Shapira, Isaac, Holtzman, Yehuda
• Primary Examiner(s): Bayard; Emmanuel
• Application Number:
  US12/026,557
• Publication Number:
  US 20080192855A1
• Time in Patent Office: 356 Days
• Field of Search: 375/346, 375/144, 375/147, 375/148, 375/347, 375/349, 375/299
• US Class Current: 375/347
• CPC Class Codes: G01S 3/023 Monitoring or calibrating
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: H04B 7/02 Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas RAKE receivers H04B1/7115
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 27/00 Modulated-carrier systems
• CPC Class Codes: H04L 27/125 using a controlled oscillator in an open loop
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/1469 using time-sharing

Abstract

Methods and systems for carrying different signals required for MIMO communication using a single coaxial cable between two endpoints of a distributed antenna system (DAS) network. Original MIMO signals having the same frequency are frequency-separated at a first endpoint of the network. The frequency-separated signals are propagated together over the single coaxial cable and then reconstructed to their original frequency at a second endpoint of the network.

Claims

1. A method for propagating multiple input multiple output (MIMO) over a distributed antenna system (DAS) network, comprising the steps of:

a) providing a plurality n of original MIMO signals;

b) at a first endpoint of the DAS network, frequency shifting n−

1 of the MIMO signals into signals with n−

1 separate frequencies, with one MIMO signal left un-shifted in frequency;

c) propagating the n−

1 frequency shifted signals and the un-shifted frequency signal together over a single coaxial cable extending for at least part of a path from the first endpoint to a second endpoint of the DAS network; and

d) at the second endpoint, reconstructing the original MIMO signals.

2. The method of claim 1, wherein the step of providing a plurality of n MIMO signals includes providing a plurality of MIMO signals belonging to a plurality of services.

3. The method of claim 1, wherein the first endpoint includes a master unit, wherein the second endpoint includes a remote unit and wherein the step of propagating includes propagating a reference frequency signal in addition to the n−

1 frequency-shifted signals and the un-shifted signal over the single co-axial cable.

4. The method of claim 3, further comprising the step of reconstructing includes reconstructing the original MIMO signal with the assistance of the reference frequency signal.

5. The method of claim 1, wherein the step of frequency shifting n−

1 of the MIMO signals into signals with n−

1 separate frequencies includes, for each of the n−

1 signals;

i) at the first endpoint, mixing the original signal with a mixing signal to create an intermediate frequency signal,ii) at the second endpoint, mixing the intermediate frequency signal with a mixing signal of the same frequency to reconstruct the original signal.

6. The method of claim 1, wherein the first endpoint is a remote unit and wherein the second endpoint is a master unit.

7. The method of claim 5, wherein the mixing the original signal with a mixing signal includes:

A) monitoring the un-shifted signal to determine the frequency of a channel associated therewith,

B) generating the mixing signal based on the frequency of the associated channel, and

C) mixing the mixing signal based on the frequency of the associated channel with the original signal.