# 1991 Sixth International Conference on Mobile Radio and Personal Communications

## Filter Results

Displaying Results 1 - 25 of 51
• ### Delivering cordless telephony in the access network using fibre-radio'

Publication Year: 1991, Page(s):45 - 48
| | PDF (184 KB)

A method of delivering cordless access is described, in which a radio distribution point (DP) is fed by an analogue optical link. Using sub-carrier multiplexing the radio path between the handset and the cordless fixed part is extended over single-mode optical fibre, in a system known as fibre-radio'. The call processing and other functions such as frequency conversion may therefore be located at... View full abstract»

• ### An assessment of the performance of linearisation schemes in the Australian MOBILESAT system by simulation

Publication Year: 1991, Page(s):74 - 76
Cited by:  Papers (2)  |  Patents (1)
| | PDF (204 KB)

The modulation schemes specified for the Australian satellite to mobile service are QPSK and ABPSK. With necessary firing both of these schemes give non-constant envelope signals and hence if efficient, and consequently nonlinear, HPAs (high power amplifiers) are to be employed in the transceivers some form of linearisation must be used. Considering digital predistortion in particular, simulations... View full abstract»

• ### Effect of dispersive fading channels on block coded modulation [mobile radio]

Publication Year: 1991, Page(s):39 - 44
| | PDF (284 KB)

Considers the effect of the mobile radio propagation environment on the distance structure of a block coded modulation scheme and discusses the implications on bit error rate performance. It is assumed that ideal equalisation is implemented, so that the combination of equaliser and decoder forms a maximum likelihood decoder for the code as transformed by the channel. Simulation results are present... View full abstract»

• ### Diversity signal processing requirements of direct sequence CDMA networks in cellular and micro-cellular environments

Publication Year: 1991, Page(s):68 - 73
Cited by:  Papers (1)
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The diversity signal processing requirements versus bandwidth efficiency of CDMA are examined for various mobile operational environments. An analytical performance model is employed to assess the spectrum efficiency aspects of various CDMA transceiver architectures operating in both rural and urban cellular environments, as well as micro-cellular network topologies. From the results presented, it... View full abstract»

Publication Year: 1991, Page(s):31 - 38
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Quadrature amplitude modulation (QAM) for digital data transmission at 32 Mbits/s over mobile radio channels is considered. At this transmission rate intersymbol interference (ISI) will generally occur, causing problems in accurately recovering the received signal. The authors consider a novel QAM equalizer which gives the wideband system superior performance to the narrowband system by virtue of ... View full abstract»

• ### Capacity improvement of CDMA systems using M-ary code shift keying

Publication Year: 1991, Page(s):63 - 67
Cited by:  Papers (8)  |  Patents (1)
| | PDF (236 KB)

A number of companies in the United States, such as QualComm, Millicom, and others, have proposed CDMA as a means of increasing the capacity of cellular systems, and have claimed that significant increases are possible. CDMA is not normally particularly bandwidth efficient. The author proposes the use of a technique called mCSK-not in itself novel-whereby its throughput may be increased significan... View full abstract»

• ### Aspects of combined coding and linear modulation and its application to future personal communication systems

Publication Year: 1991, Page(s):87 - 92
Cited by:  Patents (1)
| | PDF (272 KB)

The possibility of applying MECLCs (M-ary error correcting line codes) in conjunction with SSB transmission and linear modulation schemes is examined. Such schemes are considered to be potentially of interest for future personal communication systems. A new class of error correcting codes with defined spectra was introduced; such codes provide error control as well as a null at DC and suppressed l... View full abstract»

• ### A mixed voice and data protocol for digital cellular radio

Publication Year: 1991, Page(s):108 - 114
Cited by:  Papers (3)  |  Patents (2)
| | PDF (412 KB)

Examines several multiple access protocols to find a suitable packet transmission scheme for integrated voice and data services. The protocols which are examined are based on a TDMA frame and slot structure. Results are presented showing that PRMA (packet reservation multiple access) is a suitable option for the integrated voice and data services. This protocol provides lower speech packet loss an... View full abstract»

• ### Analysis of decision-aided DPSK in the presence of multipath fading

Publication Year: 1991, Page(s):157 - 162
Cited by:  Papers (2)
| | PDF (272 KB)

A decision-aided DPSK receiver scheme is proposed, which can achieve channel equalization using data symbols alone (i.e. no additive reference information is required). It makes use of the fact that for a typical irreducible error rate of 1%, 99% of the received symbols are correctly demodulated. Using this information to remove the modulation from the incoming radio signal effectively results in ... View full abstract»

• ### A 1.8 GHz synthesiser for use in mobile radio

Publication Year: 1991, Page(s):136 - 142
Cited by:  Papers (1)
| | PDF (400 KB)

Presents the design of a synthesiser based on a single phase locked loop, and capable of output frequencies of over 2 GHz, aimed at the portable radio market. Experimental results are presented for a prototype unit demonstrating the success of techniques to reduce the levels of phase noise and sidebands. These techniques are outlined and the results are analysed in detail. A new circuit configurat... View full abstract»

• ### Fast VQ-CELP-a speech coder for mobile radio

Publication Year: 1991, Page(s):280 - 285
Cited by:  Patents (1)
| | PDF (244 KB)

The currently emerging generation of mobile radio systems employs digital speech transmission techniques to achieve higher system capacity than analogue systems. Therefore methods of transmitting high quality digital speech signals at low bit rates are of great interest in such applications. The CELP (code excited linear prediction) algorithm is a good basis for meeting this requirement. However, ... View full abstract»

Publication Year: 1991, Page(s):21 - 25
Cited by:  Papers (1)  |  Patents (1)
| | PDF (312 KB)

The use of adaptive Viterbi detectors on fast-varying mobile-radio channels is studied. The main objective is to propose two new methods that may significantly improve the performance of the detector. The first method is to use prediction to combat the inherent delay of the channel estimates. The second method is to use so-called leaky algorithms in the channel estimator. This will make the detect... View full abstract»

• ### Average bit error rate for coherent detection in macro and micro cellular radio

Publication Year: 1991, Page(s):241 - 247
Cited by:  Papers (5)
| | PDF (384 KB)

The probability of bit error is investigated, taking account of propagation effects in macrocellular and microcellular networks, noise and multiple interferers. Coherent detection of BPSK, QPSK and BFSK is considered with combined log-normal shadowing and Rayleigh fading for macrocellular radio and combined log-normal shadowing and Rician fading for microcellular radio. The effect of interference ... View full abstract»

• ### Terminal self-location in mobile radio systems

Publication Year: 1991, Page(s):203 - 207
Cited by:  Papers (7)
| | PDF (388 KB)

The authors look at some of the work carried out during this year's study, as part of the LINK Personal Communications Programme, on the implications and practicality of self-locating intelligent mobile (SLIM) terminals, especially when used within intelligent networks. The extent to which terminal self-location can contribute to improving the efficiency of operation of the overall radio system is... View full abstract»

• ### A joint algorithm for receiver timing recovery and AFC [cellular radio]

Publication Year: 1991, Page(s):25 - 30
| | PDF (316 KB)

A combined automatic frequency control and timing recovery algorithm is discussed. This novel technique is easily implemented in sampled receivers. The algorithm requires only two samples per symbol for its operation, of the two samples, one is used for symbol decision. This technique is independent of the recovered symbols and can be applied to filtered linear modulated signals View full abstract»

• ### A reservation multiple access technique for radio-local area networks

Publication Year: 1991, Page(s):57 - 62
Cited by:  Papers (1)
| | PDF (424 KB)

The authors describe and analyse a combined random and reservation multichannel FDMA/TDMA technique which is assigned to operate in accordance with a proposed R-LAN. The effect of CSMA reservation access scheme on the overall delay and throughput performance of the system is studied. Furthermore, packet error management is also examined through the use of ARQ protocols. The results indicate that i... View full abstract»

• ### Vertical propagation of radio signals in an eleven storey building at 144 MHz

Publication Year: 1991, Page(s):83 - 86
| | PDF (204 KB)

An experimental study of vertical propagation at 144 MHz in a multi-storey building is presented. The study is relevant both to roof satellite transponding systems and potential interference to the SARSAT system from a densely packed population of personal computers. The polarisation in the case of the first application has been found essentially random at least in the horizontal plane and an empi... View full abstract»

• ### Frame by frame transmission and detection techniques for a mobile radio channel

Publication Year: 1991, Page(s):101 - 107
| | PDF (400 KB)

Considers packet data transmission over radio channels. A worst case model of a mobile radio channel is used. A useful adaptive matched-filter detection technique useful for this kind of channel with several independent fading paths has been used and found to work satisfactorily Two methods of frame by frame detection are presented. It has also been found that if the stored vectors in the modified... View full abstract»

Publication Year: 1991, Page(s):121 - 125
Cited by:  Papers (2)
| | PDF (256 KB)

Describes the cellular radio-telephone simulator which is being enveloped at BNR Europe Limited (which incorporates STL) as part of a DTI LINK programme. In order to illustrate some of the features of the simulator, two forms of channel allocation strategy and power control are considered, and results are presented View full abstract»

• ### A multi-carrier amplifier for future mobile communications systems

Publication Year: 1991, Page(s):151 - 156
Cited by:  Papers (3)  |  Patents (3)
| | PDF (292 KB)

The goal of dynamic channel allocation has eluded cellular system designers and operators alike since the concept of cellular mobile communications first became a reality. The idea of virtually instantaneous frequency re-planning of selected parts (or even all) of a cellular network has obvious attractions and alone would justify the considerable efforts being invested by a number of organisations... View full abstract»

• ### Service and operation functional architecture for personal communications

Publication Year: 1991, Page(s):212 - 217
| | PDF (328 KB)

A definition of functions composing a personal communication network and their reference model are proposed. By defining four functions, personal communications services are classified. Alternatives of information flows among these functions are also examined. Then, a practical application of the reference model to a multi-network environment is discussed together with the information flows betwee... View full abstract»

• ### The regulation of mobile communications

Publication Year: 1991, Page(s):131 - 135
| | PDF (352 KB)

Mobile communications are at the forefront of changes in the telecommunications regulatory environment, and are also affected in more ways than any other service. The following topics are discussed: use of the spectrum; regulation for competition; personal communications; regulation in practice; and the regulator's role View full abstract»

• ### A spectrum efficient cellular base-station antenna architecture

Publication Year: 1991, Page(s):272 - 279
Cited by:  Patents (25)
| | PDF (600 KB)

A multiple beam adaptive base-station antenna is proposed to complement other solutions, such a spectrum efficient modulation, currently being developed to meet the proliferating demands for enhanced capacity in mobile communications. This novel approach employs an antenna array capable of resolving the angular distribution of the mobile users as seen at the base-station site, and then utilising t... View full abstract»

• ### Tree attenuation measurements at 1-4 GHz for mobile radio systems

Publication Year: 1991, Page(s):16 - 20
Cited by:  Papers (4)
| | PDF (164 KB)

Reports measurements of the attenuation induced by trees on satellite-like paths over a wide range of frequencies (1-4 GHz). These measurements can be used to evaluate the comparable performance of mobile satellite systems at different elevation angles and over a wide frequency range. They can also provide a further insight into the applicability of the empirical formula on vegetation effects quot... View full abstract»

• ### DCS1800-the standard for PCN

Publication Year: 1991, Page(s):175 - 181
Cited by:  Papers (3)
| | PDF (400 KB)

The new standard known as Digital Cellular System at 1800 MHz (DCS 1800) was developed within ETSI GSM and Phase I was approved in February 1991. Subsequently work has continued on a combined DCS/GSM work programme in order to provide improved features and techniques based on a merged set of recommendations. The authors describe enhancements incorporated into the new standard to support PCN (perso... View full abstract»