摘要:
The present invention relates to a multi-carrier receiver for a multi-carrier system. The receiver comprises means for producing and transmitting bit number information related to the number of bits to be modulated on carriers. In accordance with an embodiment of the invention, the means are adapted to produce and transmit bit number information as parameter values for carrier subsets of contiguous carriers, and a single bit number parameter value is useable to determine the number of bits for carriers belonging to the same subset. The present invention also relates to a multi-carrier transmitter for a multi-carrier system.
摘要:
A multi-carrier receiver selects carriers (A31,A32) whereto a small amount of power and data is allocated, for estimation of characteristics of a narrowband disturber (RFI-Signal-3) in the Radio Frequency Interference band (RFI-Band), a predetermined band for e.g. radio amateur transmission. These carriers (A31,A32) can be selected amongst all carriers located inside the Radio Frequency Interference band (RFI-Band) and at least two carriers (C1,C2) located outside the Radio Frequency Interference band (RFI-Band).
摘要:
To generate a pseudo-random sequence (PRMS1) of multi-carrier data symbols (DMT0, DMT1, DMT2), a pseudo-random bit sequence (PRBS1) is produced by repetitively generating a pseudo-random sequence of L bits, L being a first integer value (L=4). To create a multi-carrier data symbol (DMT0, DMT1, DMT2) N bits are used, N being a second integer value (N=8). The pseudo-random bit sequence (PRBS1) is subdivided into strings of N' bits, N' being a third integer value larger than N (N'=9), and N bits out of each string of N' bits are used to generate a respective multi-carrier data symbol (DMT0, DMT1, DMT2). N'-N bits out of each string of N' bits are left unused.
摘要:
An integrated modem circuits comprising processor-systems (1) and hardware (2,3) for exchanging signals with another modem circuit 1 Mb/s or more are provided with low cost, accurate, flexible filter software (11) for embodying a digital phase locked loop filter. Said hardware (2,3) comprises fast modules (22,32) for compensating for sample processing. The insight of hardware phase locked loops being expensive, not accurate, inflexible and of software phase locked loops being slow results in the basic idea of the phase locked loop calculations being done in software and the compensations being done in hardware. Sample software (14,15) processes samples (shifting - adding - deleting). Said hardware (2,3) comprises in the transmission path (2) mappers (21), rotors (22) and inverse Fourier transformators (23) and in the receiving path (3) Fourier transformators (33), rotors (32) and demappers (31). Control software (12,13) controls said rotors (22,32). In software in processor-system (1) there are initialization steps (101), reading steps (102), detection steps (104,105,106,111,112,115) executing steps (108,109), adaptation steps (110,116,117), and incrementation steps (114,118).
摘要:
This application adresses the problem of synchronisation in multicarrier systems. Misalignment of symbol timing is determined by averaging the phase errors of at least two pilot tones, each weighted in accordance with the noise which affects the tone in question. When the noise which affects a pilot tone reaches a predetermined level, that pilot tone is reallocated to a different frequency, or its weight is reduced.
摘要:
A method for providing bit loading computation in a multi-carrier communication system, the method comprising measuring the signal to noise ratios (SNRs) for carriers and determining in dependence of the SNR a related number of bits to be loaded (=allocated) to the respective carrier, is characterised in that it comprises the steps of:
a) providing a sliding window, b) moving the sliding window over the frequency spectrum of the carriers, c) for each position of the window determining bit allocation for the newly introduced carrier(s), d) in the event that a predetermined average power spectrum density threshold (TPSD) of the carriers over the window is exceeded, selecting at least one carrier within the window for power spectrum density reduction at the expense of at least one bit.
摘要:
In a multi-carrier system, the carriers (f 0 ... f 511 , f 512 ... f 1023 , ..., f 3584 ... f 4095 ) are grouped in subsets (SUBSET1; SUBSET2; ...; SUBSET8). A constellation information transmitting arrangement (BiGi_TA), for instance located in the multi-carrier receiver (RX), produces for each carrier subset (SUBSET1; SUBSET2; ...; SUBSET8) a limited set of parameter values (B1, G1; B2, G2; ...; B8, G8) and transmits these sets of parameter values (B1, G1; B2, G2; ...; B8, G8) to a constellation information receiving arrangement (BiGi_RA), for instance located in the multi-carrier transmitter (TX). Through interpolation of the limited set of parameter values (B1, G1; B2, G2; ...; B8, G8) the latter constellation information receiving arrangement (BiGi_RA) determines the constellation where each carrier (f 0 ... f 511 , f 512 ... f 1023 , ..., f 3584 ... f 4095 ) of a carrier subset (SUBSET1; SUBSET2; ...; SUBSET8) will be modulated with.