function?BER4m?=?ostbc4m（M?frLen?numPackets?EbNo）
%OSTBC4M??Orthogonal?space-time?block?coding?for?4xM?antenna?configurations.
%
%???BER4M?=?OSTBC4M（M?FRLEN?NUMPACKETS?EBNOVEC）?computes?the?bit-error?rate?
%???estimates?via?simulation?for?an?orthogonal?space-time?block?coded?
%	configuration?using?four?transmit?antennas?and?M?receive?antennas?where?
%	the?frame?length?number?of?packets?simulated?and?the?Eb/No?range?of?values?
%	are?given?by?FRLEN?NUMPACKETS?and?EBNOVEC?parameters?respectively.
%
%???The?simulation?uses?a?half-rate?orthogonal?STBC?encoding?scheme?with?QPSK?
%???modulated?symbols?to?achieve?a?1?bit/sec/Hz?throughput?for?the?channel.?
%???Appropriate?combining?is?performed?at?the?receiver?to?account?for?the?
%???multiple?transmitter?antennas.
%
%???Suggested?parameter?values:
%???????M?=?1?to?4;?FRLEN?=?100;?NUMPACKETS?=?1000;?EBNOVEC?=?0:2:20;
%
%???Example:
%???????ber42?=?ostbc4m（2?100?1000?0:2:20）;
%
%???See?also?MRC1M?OSTBC2M.

%???References:
%???[1]?S.?M.?Alamouti?“A?simple?transmit?diversity?technique?for?wireless?
%???????communications“?IEEE?Journal?on?Selected?Areas?in?Communications?
%???????Vol.?16?No.?8?Oct.?1998?pp.?1451-1458.
%
%???[2]?V.?Tarokh?H.?Jafarkhami?and?A.R.?Calderbank?“Space-time?block?codes
%???????from?orthogonal?designs“?IEEE?Transactions?on?Information?Theory?
%???????Vol.?45?No.?5?Jul.?1999?pp.?1456-1467.
%
%???[3]?V.?Tarokh?H.?Jafarkhami?and?A.R.?Calderbank?“Space-time?block?codes
%???????for?wireless?communications:?Performance?results“?IEEE?Journal?on?
%???????Selected?Areas?in?Communications?Vol.?17??No.?3?Mar.?1999?
%???????pp.?451-460.

%???Copyright?2006?The?MathWorks?Inc.
%???$Revision:?1.1.6.1?$?$Date:?2006/12/27?20:28:37?$

%%?Simulation?parameters
N?=?4;??????????????%?Number?of?transmit?antennas
rate?=?0.5;?inc?=?N/rate;?repFactor?=?8;
?
%?Create?QPSK?mod-demod?objects
numBits?=?2;?
P?=?4;?		%?modulation?order
qpskmod?=?modem.pskmod（‘M‘?P?‘SymbolOrder‘?‘Gray‘?‘InputType‘?‘Integer‘）;
qpskdemod?=?modem.pskdemod（qpskmod）;

%%?Pre-allocate?variables?for?speed
txEnc?=?zeros（frLen/rate?N）;?r?=?zeros（frLen/rate?M）;
H??=?zeros（frLen/rate?N?M）;
z?=?zeros（frLen?M）;?z1?=?zeros（frLen/N?M）;?z2?=?z1;?z3?=?z1;?z4?=?z1;
error4m?=?zeros（1?numPackets）;?error4mb?=?error4m;
SER4m?=?zeros（1?length（EbNo））;?BER4m?=?SER4m;

h?=?waitbar（0?‘Percentage?Completed‘）;
set（h?‘name‘?‘Please?wait...‘）;
wb?=?100/length（EbNo）;

%%?Loop?over?EbNo?points
for?idx?=?1:length（EbNo）
????%?Loop?over?the?number?of?packets
????for?packetIdx?=?1:numPackets
????????data?=?randint（frLen?1?P）;?????????%?data?vector?per?user/channel
????????tx?=?modulate（qpskmod?data）;????????%?QPSK?modulation

????????%?Space-Time?Block?Encoder?-?G4?1/2?rate
????????%???G4Half?=?[s1?s2?s3?s4;-s2?s1?-s4?s3;-s3?s4?s1?-s2;-s4?-s3?s2?s1];
????????%???G4?=?[G4Half;?conj（G4Half）];
????????s1?=?tx（1:N:end）;?s2?=?tx（2:N:end）;?s3?=?tx（3: