Source: http://www.google.com/patents/US7587016?dq=oakley+D523,461
Timestamp: 2016-10-28 01:47:11
Document Index: 168257191

Matched Legal Cases: ['art 2', 'art 2', 'art 2', 'art 2', 'art 2', 'art 2', 'art 2', 'art 2', 'art 2']

Patent US7587016 - MIMO timing recovery - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsMultiple-input-multiple-output (MIMO) timing recovery. A novel approach is presented to perform timing recovery when processing the multiple received signals within a MIMO communication device. This may be implemented for a singular received signal, or a plurality of received signal streams. In addition,...http://www.google.com/patents/US7587016?utm_source=gb-gplus-sharePatent US7587016 - MIMO timing recoveryAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS7587016 B2Publication typeGrantApplication numberUS 11/402,572Publication dateSep 8, 2009Filing dateApr 12, 2006Priority dateJul 20, 2005Fee statusPaidAlso published asUS20070019750Publication number11402572, 402572, US 7587016 B2, US 7587016B2, US-B2-7587016, US7587016 B2, US7587016B2InventorsRohit V. Gaikwad, Rajendra Tushar MoortiOriginal AssigneeBroadcom CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (13), Referenced by (4), Classifications (8), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetMIMO timing recovery
1. U.S. Provisional Application Ser. No. 60/700,968, entitled “Carrier detection applicable for SISO, MIMO, MISO, and SIMO communications,” filed Wednesday, Jul. 20, 2005 (Jul. 20, 2005), pending.
2. U.S. Provisional Application Ser. No. 60/700,967, entitled “MIMO timing recovery,” filed Wednesday, Jul. 20, 2005 (Jul. 20, 2005), pending.
1. U.S. Utility patent application Ser. No. 11/168,793, entitled “Reduced feedback for beamforming in a wireless communication,” filed Jun. 28, 2005 (Jun. 28, 2005), pending.
As shown in a block 951, the modified correlation function is compared to a symbol timing recovery threshold (e.g., ThSTR). Also, as shown in a block 952, a peak value (or a starting value) of the modified correlation function is identified (e.g., ρAC — start 2 (nAC — start)). This peak value (or starting value) (e.g., ρ2 AC — start 2(nAC — start)) is identified when the modified correlation function exceeds the symbol timing recovery threshold (e.g., ThSTR) and when the modified correlation function is substantially non-increasing. It is noted that the modified correlation function need not necessarily be decreasing; if the modified correlation function is flat (e.g., neither increasing nor decreasing), this is sufficient to meet the criterion of this parameter.
As shown in a block 953, over a region which it is determined that the modified correlation function is in fact decreasing, a mid-point of the decreasing region of the modified correlation function is identified that, when biased by a predetermined amount, is less than the peak value of the modified correlation function. This mid-point is really a mid-point that is biased by a certain degree; this may be viewed as being performed to ensure that the mid-point is sufficiently less than the peak value (or starting value) (e.g., ρ2 AC — start 2(nAC — start)). This could be expressed mathematically as follows:
(ρ2 AC — mp 2(n AC — mp)+bias)<ρAC — start 2(n AC — start), where:
ρAC — start 2(nAC — start) is the modified correlation function at this peak value (or starting value) which is located as sample, nAC — start;
ρAC — mp 2(nAC — mp) is the modified correlation function at this mid-point value which is located as sample, nAC — mp; and
As shown in a block 954, an end-point of the decreasing region of the modified correlation function is identified that, when scaled by a predetermined scaling factor, is less than the peak value (or starting value) (e.g., ρAC — start 2(nAC — start)) of the modified correlation function. This could be expressed mathematically as follows:
(k�ρ AC — ep 2(n AC — ep))<ρAC — start 2(n AC — start), where:
ρ2 AC — start 2(nAC — start) is the modified correlation function at this peak value (or starting value) which is located as sample, nAC — start;
ρAC — ep 2(nAC — ep) is the modified correlation function at this end-point value which is located as sample, nAC — ep;
Generally speaking, this diagram shows the modified correlation function, ρmod — corr 2(n), as a function of sample, n. The modified correlation function, ρmod — corr 2(n), typically will rise and flatten out as the symbols of the STS of an OFDM packet are typically well correlated. When the LTS is encountered and processed, the symbols located therein are not typically well correlated. As such, the modified correlation function, ρmod — corr 2(n), typically falls and flattens out because of this characteristic of the symbols within the LTS of an OFDM packet. The rate of increase of the modified correlation function, ρmod — corr 2(n), and the rate of fall 1004 over a decreasing region of the modified correlation function, ρmod — corr 2(n), may be identical. As can be seen, the modified correlation function is monotonically decreasing starting when considering this region depicted by the rate of fall 1004.
For example, the symbols within the STS of an OFDM packet may be correlated very well leading to a very rapid rise of the modified correlation function, ρmod — corr 2(n). However, the symbols within the LTS of an OFDM packet may be somewhat correlated initially and then very poorly correlated thereafter leading to a relatively slow rate of fall 1004. Alternatively, the symbols within the LTS of an OFDM packet may very poorly correlated from the very beginning leading to a very precipitous rate of fall 1004.
ρAC — start 2(nAC — start) (peak value) 1001 is the modified correlation function at this peak value (or starting value) which is located as sample, nAC — start;
ρAC — mp 2(nAC — mp) (mid-point) 1002 is the modified correlation function at this mid-point value which is located as sample, nAC — mp; and
ρAC — ep 2(nAC — ep) (end-point) 1003 is the modified correlation function at this end-point value which is located as sample, nAC — ep.
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