Thus, the channel capacity (bandwidth efficiency) can be written as follows: C WLAN = 1 BW ∑ k = 1 N f C k narrowband bits / s / Hz, (7).
The time-domain and frequency-domain envelope parameters are extracted from the high-frequency components of speech signal, and then these parameters are embedded in the corresponding narrowband speech bit stream by the modified least significant bit watermark method which uses perception property.
This method first extracts the necessary HF components parameters, including time-domain envelopes, frequency-domain envelopes, and energy of the wideband speech; then these parameters are compressed and embedded into the narrowband speech bit stream with a modified watermark technique.
United, instead, is emphasizing its $9.95-a-month 9.95-a-monthso-called narrowband, service at 56,000 bits a second.
(a) Eb/N0 = 10 dB; (b) Eb/N0 = 20 dB. Figure 7 The error bit probability without narrowband interference.
At the decoder, the wideband speech is reproduced with the reconstruction of high-frequency components based on the parameters extracted from bit stream of the narrowband speech.
Moreover, simulations conducted in a digital subscriber line (DSL -like environment contaminateDSL -likerrowband noisenvironment the acontaminatedt rate of the proposed transceiver is significantly higher than that of a conventional OFDM system.
With narrowband signals (such as GSM), e.g., 14-bit resolution can be achieved with 1-bit quantization because of high oversampling and digital filtering.
The high-frequency speech information as watermark is embedded in the narrowband (i.e., low-frequency) speech bit stream.
The watermark message is defined as a sequence of randomly generated bits that each bit is spread using a narrowband PN sequence, then shaped using BPSK modulation and an embedding strength.
