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| In [[telecommunication]]s, '''maximal-ratio combining''' ('''MRC''') is a method of [[diversity combining]] in which:
| | I'm Benny (31) from Uppsala, Sweden. <br>I'm learning Norwegian literature at a local college and I'm just about to graduate.<br>I have a part time job in a post office.<br><br>Have a look at my web-site; [http://12hourcureforyeastinfectiondownload.blogspot.com/ 12 Hour Cure For Yeast Infection Download] |
| #the signals from each [[channel (communications)|channel]] are added together,
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| #the [[gain]] of each channel is made [[Proportionality (mathematics)|proportional]] to the rms [[signal level]] and inversely proportional to the mean square [[noise level]] in that channel.
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| #different proportionality constants are used for each channel.
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| It is also known as '''ratio-squared combining''' and '''predetection combining'''. Maximal-ratio combining is the optimum combiner for independent [[Additive white Gaussian noise|AWGN]] channels.
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| MRC can restore a signal to its original shape.
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| == Example: Least Squares estimate in the case of Rx diversity ==
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| We consider an example of which the receiver is endowed with N antennas. In this case, the received vector <math>y</math> is
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| {{NumBlk|:|<math>y=hs+\rho n \,</math>|{{EquationRef|1}}}}
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| where <math>n</math> is noise vector <math>n-CN(0,I_{N \times N})</math>. Following the ML detection criterion the detection procedure may be written as
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| {{NumBlk|:|<math>\tilde{s}=argmin_{s \in QPSK}|\hat{s}-s|^2,</math>|{{EquationRef|2}}}}
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| where <math>\hat{s}</math> is the least square solution to the above model.
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| {{NumBlk|:|<math>\hat{s}=(h^*h)^{-1}h^*y.</math>|{{EquationRef|3}}}}
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| The least square solution in this case is also known as maximal-ratio-combining (MRC). In the case of N antennas the LS can be written as
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| {{NumBlk|:|<math>\hat{s}=\frac{h_0^*y_0+h_1^*y_1+...+h_{N-1}^*y_{N-1}}{|h_0|^2+|h_1|^2+...+|h_{N-1}|^2},</math>|{{EquationRef|4}}}}
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| which means that the signal from each antenna is rotated and weighted according to the phase and strength of the channel, such that the signals from all antennas are combined to yield the maximal ratio between signal and noise terms.
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| == See also ==
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| [[Diversity combining]]
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| {{FS1037C MS188}}
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| {{DEFAULTSORT:Maximal-Ratio Combining}}
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| [[Category:Telecommunications techniques]]
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| [[Category:Radio resource management]]
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| {{telecomm-stub}}
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I'm Benny (31) from Uppsala, Sweden.
I'm learning Norwegian literature at a local college and I'm just about to graduate.
I have a part time job in a post office.
Have a look at my web-site; 12 Hour Cure For Yeast Infection Download