Bit error rate

A detailed discussion of coded modulation is beyond the scope of this paper. Our main goal is to demonstrate that, with R = I, low bit-error rates (pb < 10 ) can be achieved within 1.6 dB of the maximal achievable rate of SCS. Fig. 7 shows... 

Figure 7. Measured bit-error rate p6 for rate 1 bit/element are shown for 4-ary convolutional coded trellis coded modulation (CC-TCM), 4-ary multilevel coded modulation with rate assigmnent of i o = 1/7 and Ri =6/7 (ML-1/7-6/7), or i o = 1/5 and i i = 4/5 (ML-1/5-4/5), and 8-aty serial concatenated trellis coded modulation (SC-TCM).

Chou et al. proposed a blind watermarking scheme where an optimization algorithm is used to design the codebook U. They presented simulation results for different versions of their approach at bit-error rates of p6 < 10 and a watermark rate R = 1 bit/element. Their best scheme operates at WNR > lOdB. Thus, SCS combined with coded modulation outperforms the approach of Chou et al. by about 0.7 1.7 dB. 

Figure 15. Reliable coded binary (ST-)SCS compared with theoretical hmits. The measured points indicate the minimal WNR for that a specific coding technique achieves a bit-error rate p, < 10 .

Bit-error rates (BERs) around 10-5 are achieved by CC-TCM and SC-TCM for WNR > 9.3 dB. The best performance for BER < 10-5 was achieved by SC-TCM, with a minimum required WNR 8.3 dB. However, note that the computational complexity of ST-TCM and the codeword length (10,000 information bits) is also quite large compared to CC-TCM. Fig. 10 compares the measured minimum WNR for achieving BER < 10 5 with SC-TCM and CC-TCM with the capacity of SCS and ICS. Ideally, SCS with R = 1 bit/element is possible for WNR > 6.7 dB. Thus, the discussed coded modulation... 

The result in the table shows that in all the cases the bit error rate is close to 50%. Thus, the attack is successful. We present the images in Figure 1. Note that the attacked images are visually indistinguishable from the original or watermarked images. 

A well-known adverse effect in body-centric communications is caused by fading and shadowing of a signal received by a moving subject equipped with a wearable antenna system. These phenomena are a consequence of multipath propagation and have a negative effect on power consumption. In parficular, these random fluctuations on the received signal produce an increase of the bit error rate (BER). 

The jamming of a communication link is often viewed as a game. The transmitter can deliver a fixed amount of power S to the receiver, and the end user specifies a maximum allowable bit error rate (BER). 

Shannon showed that to every communication channel we can associate a channel capacity C, and that there exist error correcting codes such that information can be transmitted across a noisy channel at rates less than C, with arbitrarily low bit error rate. In fact, an important implication of Shannon s theory is that it is wasteful to build a channel that is too good it is more economical to use an appropriate code. Until Shannon s discovery, it was believed that the only way to overcome channel noise was to use more powerful transmitters or build larger antennas. 

Channel capacity The maximmn information rate that can be transmitted across a channel, with arbitrarily low bit error rate. 

For digital modulation systems, bit error rate (BER) is related to the dimensionless ratio (decibel difference) of energy per bit, dB 1 to the total noise power density N = 10 log(fcT) dB J (Sklar, 1988). For thermal... 

Burst channel errors. Wireless channels experience higher bit error rate than wireline transmissions. Besides, errors occur in bursts as the signal fades, resulting in high probability of packet loss. Therefore, an acknowledgement mechanism must be implemented so that the packet retransmission maybe possible in case of packet loss. 

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