GSM voice evolution using orthogonal subchannels

Paiva, Rafael C. D.; Vieira, Robson D.; Iida, Renato F.; Tavares, Filipe; Säily, Mikko; Hulkkonen, Jari; Jarvela, R.; Niemela, K.

doi:10.1109/mcom.2012.6384455

Cited by 5 publications

(10 citation statements)

References 6 publications

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“…In the past 10 years, there has been a significant increase in the number of GSM users [1]. Because mostly voice services are requested, there is a need for a major voice capacity enhancement within the GSM system in order to meet the demands of the customers.…”

Section: Introductionmentioning

confidence: 99%

“…However, joint detection schemes are quite complex and restricted to synchronous networks. Another recent development in GSM is the capacity increase for voice connections introduced by the Voice services over Adaptive Multi-user channels on One Slot (VAMOS) [1] extension. Here, two user signals are deliberately overlaid and transmitted at the same time and in the same frequency band.…”

Section: Introductionmentioning

confidence: 99%

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Single Antenna Interference Cancellation for GSM/VAMOS/EDGE Using <inline-formula> <tex-math notation="TeX">$L_{p}$</tex-math></inline-formula>-Norm Detection and Decoding

Ruder

Lehmann

Schober

et al. 2015

IEEE Trans. Wireless Commun.

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Different schemes for single antenna interference cancellation (SAIC) in the Global System for Mobile Communications (GSM) have been proposed so far. Most of these schemes work best in synchronous interference environments and are limited to Gaussian minimum-shift keying (GMSK) modulation. In this paper, we propose several modifications of the conventional GSM receiver, which target the harmful effects of asynchronous co-channel interference (ACCI). Based on the observation that the impairment caused by ACCI cannot be modeled as additive Gaussian noise, which was assumed for the derivation of the metric used in state-of-the-art receivers, we propose to model the impairment as Generalized Gaussian noise (GGN). This leads to modifications of the conventional branch metrics of the reduced-state equalizer and the decoder employed at the receiver. Both proposed modifications are applicable to any linear modulation alphabet and do not require any modification of the GSM air interface. Hence, the proposed novel branch metrics are also applicable in Enhanced Data Rates for GSM Evolution (EDGE) systems which employ 8-ary phase-shift keying (8-PSK) modulation and where the SAIC algorithms tailored for GMSK cannot be used. Furthermore, we show that the proposed branch metric modifications also improve the performance of the new Voice Services over Adaptive Multi-user channels on One Slot (VAMOS) extension of GSM in ACCI environments. Based on simulation results, the performance of the proposed schemes is compared with that of an unmodified receiver employing the conventional Gaussian metric. We show that the proposed receivers outperform the unmodified receiver in ACCI environments and discuss the complexity entailed by the proposed branch metric modifications.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Single Antenna Interference Cancellation for GSM/VAMOS/EDGE Using <inline-formula> <tex-math notation="TeX">$L_{p}$</tex-math></inline-formula>-Norm Detection and Decoding

Ruder

Lehmann

Schober

et al. 2015

IEEE Trans. Wireless Commun.

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“…Despite the important development of 3G and 4G mobile cellular networks all over the world for data and video traffic, there is still a significant development of GSM/EDGE networks and their evolutions in emerging markets such as China, India, Africa and Eastern Europe [16]. To accommodate the growing voice traffic and also to make room for increasing data traffic, there is a necessity to increase the spectral efficiency of speech services.…”

mentioning

confidence: 99%

“…To accommodate the growing voice traffic and also to make room for increasing data traffic, there is a necessity to increase the spectral efficiency of speech services. For this reason, a new technology, called VAMOS, has been recently standardized [16]. The aim of VAMOS is to increase the capacity of GSM, while maintaining backward compatibility with the legacy system.…”

mentioning

confidence: 99%

“…VAMOS enables the transmission of two GSM voice streams on the same TDMA slot at the same carrier frequency through the so-called orthogonal sub channel (OSC) multiple access technique which aims at doubling the number of users served by a cell. The separation, at the handset level, of the two streams, distorted by frequency selective channels and potentially corrupted by co-channel OSC and/or legacy GMSK interference, coming from out of cell OSC and/or legacy base-stations, requires the implementation of enhanced SAIC techniques for QR signals [16]. Such preliminary enhanced techniques for VAMOS, based on standard WL filtering, have been proposed recently in [17][18][19] for SAIC and in [20] for SAIC/MAIC, for both OSC downlink and uplink transmissions respectively.…”

mentioning

confidence: 99%

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Enhanced Widely Linear Filtering to Make Quasi-Rectilinear Signals Almost Equivalent to Rectilinear Ones for SAIC/MAIC

Chevalier

Chauvat

Delmas

2018

IEEE Trans. Signal Process.

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Abstract-Widely linear (WL) receivers have the capability to perform single antenna interference cancellation (SAIC) of one rectilinear (R) or quasi-rectilinear (QR) co-channel interference (CCI), a function which is operational in global system for mobile communications (GSM) handsets in particular. Moreover, SAIC technology for QR signals is still required for voice services over adaptive multi-user channels on one slot (VAMOS) standard, a recent evolution of GSM/EDGE standard, to mitigate legacy GSM CCI in particular. It is also required for filter bank multi-carrier offset quadrature amplitude modulation (FBMC-OQAM) networks, which are candidate for 5G mobile networks, to mitigate inter-carrier interference (ICI) at reception for frequency selective propagation channels in particular. In this context, the purpose of this paper is twofold. The first one is to get more insights into the existing SAIC technology, and its extension to multiple antenna called MAIC, by showing analytically that, contrary to what is accepted as true in the literature, SAIC/MAIC implemented from standard WL filtering may be less efficient for QR signals than for R ones. From this result, the second purpose of the paper is to propose and to analyze, for QR signals and frequency selective fading channels, a SAIC/MAIC enhancement based on a three-input WL frequency shift (FRESH) receiver, making QR signals always almost equivalent to R ones for WL filtering in the presence of CCI. The results of the paper, completely new, may contribute to develop elsewhere new powerful WL receivers for QR signals and for both VAMOS and FBMC-OQAM networks in particular.

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Quasi-rectilinear (MSK, GMSK, OQAM) co-channel interference mitigation by three inputs widely linear fresh filtering

Chevalier¹,

Chauvat²,

Delmas³

2015

2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

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Widely linear (WL) filters have the capability to perform single antenna interference cancellation (SAIC) of one rectilinear or quasi-rectilinear (QR) co-channel interference (CCI). The SAIC technology for QR signals is operational in GSM handsets but requires enhancements for both VA-MOS standard, an evolution of GSM/EDGE standard, and FBMC-OQAM networks, which are candidate for 5G mobile networks. In this context, we propose and analyze in this paper, for QR signals, a SAIC/MAIC enhancement based on the concept of three inputs WL FRESH filtering, exploiting almost exhaustively both the non-circularity and the cyclostationnarity of QR signals, contrary to classical approaches which only exploit very partly these properties.

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GSM voice evolution using orthogonal subchannels

Cited by 5 publications

References 6 publications

Single Antenna Interference Cancellation for GSM/VAMOS/EDGE Using <inline-formula> <tex-math notation="TeX">$L_{p}$</tex-math></inline-formula>-Norm Detection and Decoding

Single Antenna Interference Cancellation for GSM/VAMOS/EDGE Using <inline-formula> <tex-math notation="TeX">$L_{p}$</tex-math></inline-formula>-Norm Detection and Decoding

Enhanced Widely Linear Filtering to Make Quasi-Rectilinear Signals Almost Equivalent to Rectilinear Ones for SAIC/MAIC

Quasi-rectilinear (MSK, GMSK, OQAM) co-channel interference mitigation by three inputs widely linear fresh filtering

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