simthlib::ofdm Namespace Reference

Enumerations
enum	FillUpScheme { TIME, TIME_SNAKE, FREQ, FREQ_SNAKE }
Functions
ofdm::FillUpScheme	string_to_diffscheme (const std::string &s)
void	initFillUpScheme (FillUpScheme mode, int numOfdmSymbols, int numCarrier, simth::checkedVector< int > *vec)
std::pair< int, int >	index2position (int index, int numCarrier)
int	position2index (int timePos, int carrierPos, int numCarrier)

---

Detailed Description

The function in these namespace are used within the OFDM Transmitter and OFDM receiver classes.

Whoever intends to extend those classes or one who wants to understand the functions defined in this namespace should understand the concept used to address the data elements inside a transmitted or received OFDM block:

An OFDM block consist of one or more received OFDM symbols. Each of the these OFDM symbols itself consist of a certain number of modulation symbols. For example, the third modulation symbol of the first OFDM symbol can be accessed in 2-dimensional notation as '(0,2)' (note that the index starts at zero). Since the received OFDM symbols arrive to successive time stamps, the first dimension (that indexes a certain OFDM symbol) is called the time index, while the second index (that indexes a certain subcarrier number) is called the frequency index. This 2-dimensional index can be translated into an one dimensional, so called 'ofdmIndex', using the function position2index(int timePos,int freqPos). This 'ofdmIndex' is for internal use only (it results if the modulation symbols are counted columnwise starting from the left bottom corner). The inverse operation is done by the function index2position(int ofdmIndex).

Since different schemes exist to fill the OFDM with received modulation sequences, the ofdmIndex of a data element does not equal (in general) the index of that element in the received input sequences of modulation symbols. (The different 'filling modes' are set with the function fillUpMode(FillUp_Mode).) This index of the modulation symbol within the input (as well as within the output sequence) can be computed by the 'ofdmIndex' using the function ofdmIndex2origIndex(int ofdmIndex).

---

Enumeration Type Documentation

enum simthlib::ofdm::FillUpScheme

Enumeration values: TIME  TIME_SNAKE  FREQ  FREQ_SNAKE

---

Function Documentation

std::pair<int,int> index2position (  int  index, int  numCarrier )

Converts the 1-dimensional index that describes a position within the OFDM block to the 2-dimensional notation. The first dimension of that notation indexes the time position, i.e. the OFDM symbol while the second dimension indexes the frequency position, i.e. the subcarrier number. The lower left corner is indexed by (0,0), the upper left corner is

void initFillUpScheme (  FillUpScheme  mode, int  numOfdmSymbols, int  numCarrier, simth::checkedVector< int > *  vec )

int position2index (  int  timePos, int  carrierPos, int  numCarrier )

The inverse operation of the function index2position(int index).

ofdm::FillUpScheme string_to_diffscheme (  const std::string &  s  )

Converts a string specification of the fill-up scheme (e.g. from the parameter file or Property) into the appropriate enum value.

---