Area spectral efficiency of soft-decision space–time–frequency shift-keying-aided slow-frequency-hopping multiple access

Slow-frequency-hopping multiple access (SFHMA) can provide inherent frequency diversity and beneficially randomize the effects of cochannel interference. It may also be advantageously combined with our novel space-time–frequency shift keying (STFSK) scheme. The proposed system’s area spectral efficiency is investigated in various cellular frequency reuse structures. Furthermore, it is compared to both classic Gaussian minimum shift keying (GMSK)-aided SFHMA and GMSK-assisted time- division/frequency-division multiple access (TD/FDMA). The more sophisticated third-generation wideband code-division multiple access (WCDMA) and the fourth-generation Long Term Evolution (LTE) systems were also included in our comparisons. We demonstrate that the area spectral efficiency of the STFSK-aided SFHMA system is higher than the GMSK-aided SFHMA and TD/FDMA systems, as well as WCDMA, but it is only 60% of the LTE system

A novel scheme to aid coherent detection of GMSK signals in fast Rayleigh fading channels

A novel scheme to insert carrier pilot to Gaussian Minimum Shift Keying (GMSK) signal using Binary Block Code (BBC) and a highpass filter in baseband is proposed. This allows the signal to be coherently demodulated even in a fast Rayleigh fading environment. As an illustrative example, the scheme is applied to a 16 kb/s GMSK signal, and its performance over a fast Rayleigh fading channel is investigated using computer simulation. This modem's 'irreducible error rate' is found to be Pe = 5.5 x 10(exp -5) which is more than that of differential detection. The modem's performance in Rician fading channel is currently under investigation

Error rate analysis for indoor wireless networks

An attempt is made to predict the maximum data rates for a typical wireless computer network operating in an indoor frequency-selective environment. To lower the error rates for high-speed data transmission, the impact of techniques such as diversity combining, frequency hopping, and pulse shaping is investigate

A hybrid voice/data modulation for the VHF aeronautical channels

A method of improving the spectral efficiency of the existing Very High Frequency (VHF) Amplitude Modulation (AM) voice communication channels is proposed. The technique is to phase modulate the existing voice amplitude modulated carrier with digital data. This allows the transmission of digital information over an existing AM voice channel with no change to the existing AM signal format. There is no modification to the existing AM receiver to demodulate the voice signal and an additional receiver module can be added for processing of the digital data. The existing VHF AM transmitter requires only a slight modification for the addition of the digital data signal. The past work in the area is summarized and presented together with an improved system design and the proposed implementation

Channel selection requirements for Bluetooth receivers using a simple demodulation algorithm

In our Software Defined Radio (SDR) project we combine two different types of standards, Bluetooth and HiperLAN/2, on one common hardware platform. SDR system research aims at the design, implementation and deployment of flexible radio systems that are reprogrammable and re-configurable by software. Goal of our project is to generate knowledge about designing the front end of an SDR system (from the antenna signal to the channel bit stream) where especially an approach from both analog and digital perspective is essential. This paper discusses the channel selection requirements for the Bluetooth standard. The standard specifications specify only the power level of the interferers, the power level of the wanted signal and the maximum allowed Bit Error Rate (BER). In order to build a radio front-end, one has to know the required (channel) suppression of these interferers. From [1] it is known that the required SNR for a Bluetooth demodulator is 21 dB, but by which value should interferers be suppressed? This paper will validate if the SNR value needs to be used for the suppression of adjacent channels. In order to answer this question a simulation model of a Bluetooth radio front-end is built

Application of hidden markov models to blind channel estimation and data detection in a gsm environment

In this paper, we present an algorithm based on the Hidden Markov Models (HMM) theory to solve the problem of blind channel estimation and sequence detection in mobile digital communications. The environment in which the algorithm is tested is the Paneuropean Mobile Radio System, also known as GSM. In this system, a large part in each burst is devoted to allocate a training sequence used to obtain a channel estimate. The algorithm presented would not require this sequence, and that would imply an increase of the system capacity. Performance, evaluated for standard test channels, is close to that of non-blind algorithms.Peer ReviewedPostprint (published version