The purpose behind the creation of this Interim Standard 124 is to provide a means of exchanging wireless subscriber usage information in a near real time basis. The present means of data exchange is typically done in batch mode through the use of magnetic tape.
Fiber optics has become an important medium in the development of worldwide cellular system microcell and remote antenna applications. Several products are available which take advantage of single mode 1310 and 1550 nm fiber optic transmission and its low loss and relative ease of installation. This paper presents a brief history of RF transmission technology, summarizes the technical aspects of the RF to light conversion, and describes the Allen Telecom fiber-based microcell and active antenna products while presenting examples of applications.
In this communication we consider the use of an optical fiber based fixed infrastructure for code division multiple access (CDMA) mobile networks. In such a scenario, the base stations are linked to the central station through optical fiber using subcarrier multiplexing (SCM) technology. One of the major problems associated with optical SCM is the nonlinearity of the laser diodes (LD). In this communication we model the LD as a memoryless nonlinearity and evaluate the effect of the nonlinearity on the SCM transmission CDMA signals. We find that the behavior departs significantly from what happens in FDMA and depends critically on the nonlinearity of the LD being a compressing or an expanding one. In the former case significant performance degradation may occur whereas for the latter the degradation is usually not dramatic.
Established wireless services continue to grow at healthy rates and new wireless services continue to emerge. The result is that there will be multiple networks offering connectivity. As applications grow on these services, subscribers will need cross functionality between these wireless networks. Additionally, as subscribers demand indoor coverage for these services, indoor environments could begin to look like outdoor environments with their multitude of systems and antennas. This paper will articulate several proposed architectures for in-building wireless services that can span the different frequencies, air standards and network interfaces to offer a seamless environment.
Wireless location systems offer carriers the opportunity to enhance revenues, reduce unwanted costs, and meet public safety requirements. The primary applications include support for emergency 911 systems, support for arresting and prosecution fraud perpetrators, and location sensitive billing. Once a wireless location system has been built for any one major application, many incremental applications can be inexpensively added.
Most modern computer applications consists of functional pieces that perform the following functions: Input Processing-Interactive and/or Batch, Database Storage and Access, Data Analysis and Output Generation. Developing an application to meet a static set of requirements is hard enough, but in real world applications, Extensibility, Scaleability, Customizability, Maintainability, and ability to adopt and leverage new technologies are key issues. When addressed up-front using proper Design and Architectural guidelines and methodology, you can reduce the effort on subsequent releases of products by an order of magnitude. This discussion covers methods to incorporate interfaces of evolving standards in your applications as well as techniques for encapsulation of various functional interfaces to provide highly customizable and functional applications that can be quickly deployed.
The Wireless Intelligent Network (WIN) intends to take advantage of the Advanced Intelligent Network (AIN) concepts and products developed from wireline communications. However, progress of the AIN deployment has been slow due to the many barriers that exist in the traditional wireline carriers' deployment procedures and infrastructure. The success of AIN has not been truly demonstrated. The AIN objectives and directions are applicable to the wireless industry although the plans and implementations could be significantly different. This paper points out WIN characteristics in architecture, flexibility, deployment, and value to customers. In order to succeed, the technology driven AIN concept has to be reinforced by the market driven WIN services. An infrastructure suitable for the WIN will contain elements that are foreign to the wireline network. The deployment process is expected to seed with the revenue generated services. Standardization will be achieved by simplifying and incorporating the IS-41C, AIN, and Intelligent Network CS-1 recommendations. Integration of the existing and future systems impose the biggest challenge of all. Service creation has to be complemented with service deployment process which heavily impact the carriers' infrastructure. WIN deployment will likely start from an Intelligent Peripheral, a Service Control Point and migrate to a Service Node when sufficient triggers are implemented in the mobile switch for distributed call control. The struggle to move forward will not be based on technology, but rather on the impact to existing infrastructure.
As a result of zoning and increasing capitol expense, radio frequency transmitting sites are becoming more populated. 800 MHz cellular base stations utilize many close spaced frequency channels. The receivers and transmitters associated with these stations can produce intermod products which can impair the performance of these systems. Careful attention must be given to frequency planning, hardware integration and environmental factors. This paper will outline the problem of intermodulation interference, 800 MHz cellular frequency planning and site considerations.
There is no doubt about it: Asynchronous Transfer Mode (ATM) traffic will soon connect to the wireless network. Its characteristics are very well adapted to provide a well-balanced mix of voice and data communications. The question here is where will adaptation layers be processed? Should the Wireless Carrier be burdened with converting ATM-based traffic in other interfaces such as Cellular Digital Packet Data, a solution leading to multiple and possibly unmanageable gateway functions? Or should an Air Interface be developed to carry ATM traffic? Pushing ATM adaptation layers closer to the point of consumption of voice, data or video holds many advantages. This paper attempts to shine some light on the subject.
Within the context of a layered view of cellular systems, how new services can be offered over existing cellular communications infrastructure is described. Within a layered system, it is possible to add new layers to offer additional services without requiring modification to existing layers. Examples of how cellular service enhancements have been provided in the past are illustrated in this layered view, as well as pointing directions for possible future improvements. Within the context of this viewpoint, it is argued that AMPS may continue to provide a basis for enhanced cellular services.
Various types of location systems have been proposed for locating cellular telephones. In location systems examined by and field tested by Associated Group, time different of arrival systems have proven to yield the best performance for the signals transmitted by AMPS cellular telephones. The reverse control channel transmissions were identified as the preferred channel to locate due to signal characteristics.
RF signature technologies offer the next step in combating wireless fraud. Utilizing technologies developed for the military, RF signature solutions bring precall methodologies to the fraud arsenal. As with network-based authentication, the challenge is to integrate the detection, analysis, and interdiction processes to allow intersystem and inter-vendor coverage, effectively shutting out home and roaming fraud.
Existing cellular networks handle voice traffic by using narrowband, single-technology equipment. More recently-developed radio interface standards such as TDMA and CDMA use different technology and equipment and are incompatible with the existing cellular infrastructure. The needs of wireless customers are also changing dramatically. Typical users will soon expect to be able to transmit data as well as voice. In the immediate future, users will demand advanced features such as one phone number, called ID, location ID, all of which require new technology and radio standards. To meet the need for transporting data, cellular network providers are adding equipment to transport data over existing cellular networks via CDPD. With the advent of dual technology, network providers will be able to satisfy customers' needs and increase their revenue--without installing additional data equipment. Dual technology will provide simultaneous support for incompatible standards and also supply a migration path to the advanced features of future digital phones.
A theoretical approach that uses minimum a priori information of sources parameters, their locations in the space and propagation properties is developed to predict EMI parameters in urban zone, where the communication systems are normally operated. The model is given by an exact and simplified evaluation. The exact evaluation is applied to statistical moments, APD, VD, and LD; the simplification in accordance with the Gamma distribution and conception of average distance is done. As an example, the model is used to predict the interferences level in radio systems for the range frequency VHF/UHF in a zone of Mexico city.
The purpose of this paper is to describe the flow of calls through the mobile network as it applies to the operation of Basic and Enhanced Services. Included in the discussion is the overall network layout, the physical connections between the network entities, and the signaling protocols which allow the entities to be integrated. The specific functionality of the applications and services are not detailed as the specific implementation varies from vendor to vendor and from service provider to service provider. The Enhanced Services Platform is installed in a service providers network in order to offer mobile subscribers services and applications which would otherwise not be available. The service providers' objective is to increase revenue/subscriber, increase subscriber loyalty/decrease churn, and build competitive advantages through differentiation. The services provided on the Enhanced Services platform can be viewed as either Basic or Enhanced. For the purpose of this paper, Basic Services refers to Numeric Paging, Call Answering, and Voice Messaging while Enhanced Services refers to FAX Messaging, One Number Service, Voice Dialing and other Voice Recognition applications, Information Services including FAX on Demand, and Automated Call Routing.
This transcript is about MobileComm's vision of Narrow-band PCS. The process started when we were anxiously watching the auctions last July and MobileComm was fortunate enough to win one of the Nationwide PCS frequencies. Since that time there has been a lot of questions asked, What exactly is PCS? How is MobileComm going to implement it? How does that differ from what our competitors are doing?'
The link budget determines the relationships between range, capacity and transmitted power for any wireless technology. In every case it is a key determinant of the system's performance from both an engineering and an economic point of view. Unfortunately, the new 1.9 GHz PCS systems will begin life with an inherent 7 dB disadvantage over the 800 MHz cellular due to propagation differences. Additionally, system wiring and electronics often degrade performance by a further 5 to 10 dB due to long coaxial runs and noisy front end amplification, both of which are harder issues to deal with at 1.9 GHz than at 800 MHz. SCT's REACHTM products address these shortcomings by packaging critical components--front end amplification, filtering, etc.--in a compact cryoelectronic package intended for mounting near the antennas of the base station. In a recent trial with Qualcomm in San Diego, this package improved the CDMA uplink budget by 6 dB--enough to halve the number of base stations that are needed in most areas. This paper examines the technical and economic ramifications of the REACHTM product.
Many alternatives currently exist for voice-channel bandwidth systems capable of delivering wireless data. However, almost all of them are oriented around the voice-circuit paradigm. While this paradigm is eminently suitable for the voice links it was designed to serve, it is quite inefficient for the relatively short, bursty messages that characterize the majority of mobile digital-messaging. Moreover, these narrow-band technologies only provide a part of the mobile resource management communication solution. A very large number of mobile applications benefit greatly from knowledge of the mobile's location. This has typically been supplied by secondary technologies, such as Dead-Reckoning, LORAN or more recently GPS. This paper will introduce a new technology that can provide fast, high-capacity, low-cost, mobile packet-data and simultaneous high-resolution radio-location from a single message stream transmitted by the vehicular mobile radio. It is based on an RF technology evolved from modern spread spectrum radar and on a unique airtime management protocol.
Several types of high gain multibeam antennas were tested and compared to traditional sector and omni antennas in various mobile radio environments. A vehicle equipped with a mobile transmitter drove in several mobile radio environments while the received signal strength (RSS) was recorded on multiple antenna channels attached to multibeam, sector and omni directional antennas. The RSS data recorded included the fast (rayleigh) fading and was averaged into local means based on the mobile's position/speed. Description of the experiment and analysis of the gain improvement, average RSS, diversity gain are presented.
Multimedia on standalone and LAN based desktop computers is exploding. Multimedia markets are growing, applications are serving new areas, available processing power is increasing, network bandwidth is increasing, and technology developments are providing new capabilities. However, multimedia development in a wireless or mobile environment is not growing at the same rate at LAN based applications. Much attention has been placed on wireless device design including power management in an attempt to increase the wireless device's capability in step with a desktop device. However not much attention has been placed on the issue of bringing multimedia applications into the mobile operating environment. This paper examines some of the issues involved with bringing multimedia applications from the desktop to the mobile environment. The interaction with mobility management is explored in terms of multimedia messaging applications.
This paper contains Cellular/PCS mobile data and voice requirements with regards to network performance and architecture to suggest that wide area data and voice are convergent rather than divergent. The paper motivates a further integration of the existing Cellular Digital Packet Data and asynchronous data services with today's TDMA/CDMA air-interface standards and within the network and subscriber unit. The paper concludes by suggesting even more extensive voice and data integration based on the B-ISDN model for the future third generation wireless communications systems.
We consider the organization of the information in video sequences for transmission over an integrated wireless access network carrying a wide variety of services at different bit rates. The access network employs direct-sequence code-division multiple access at bandwidths of 5 or 15 MHz. Video calls at 64 kb/s or voice calls at a peak rate of 8 kb/s are admitted on demand depending on the existing interference profile within a cell and its neighborhood. The transmission of QCIF resolution video sequences at 10 frames/sec has been simulated. The video information is packetized into two priority layers, a high priority layer and a discardable enhancement layer. In addition to FEC, we employ an ARQ protocol with retransmission time-out set at 1 frame interval or 100 ms. With transmission power appropriate to bit error rates of 10-4, picture loss rates of less than one per hour can be achieved.
Enhanced services for mobile subscribers are currently undergoing significant growth. This growth will continue to increase as more wireless serviceproviders enter the marketplace. Profit margins for basic service will fall as competition increases leading to interest in higher margin enhanced services. Likewise subscribers will demand enhanced services to further increase productivity over basic wire service. However there are limitations in today's network infrastructure defined by inter-system interface standards such as IS-41, GSM and WACS. These network limitations prevent enhanced services from being offered in the seamless and geographically ubiquitous fashion subscribers are familiar with in basic wireless service. This paper examines what are the needs of wireless enhanced services to be provided as subscribers want them. This paper then looks at the major inter-system interfaces available for mobility and call control in terms of how well these enhanced service needs are fulfilled.
Heterogeneous networks mix wired and wireless technologies, exhibiting well over three orders of magnitude of throughputs. Mobility adds the challenge of dynamic abrupt changes in the throughput experienced by a user. We describe in this paper a video service architecture that accommodates these widely different operating environments while providing graceful degradation as conditions change dynamically for mobile users. The video service is designed in the context of CMU's wireless Andrew. Key to our architecture is Generative Video (GV), a meta representation for video sequences. GV reduces video to still images, the world images, and ancillary data. The world images integrate the information about the background and about all moving objects present in the sequence. World images `lossless' compress the video sequence by at least two orders of magnitude. When coupled with spatial compression of these still images, the total compression ratio can easily exceed three orders of magnitude, well beyond the possibilities of current technologies. Scalable encoding of GV reduces to scalable encoding of still images. We discuss three alternatives, frequency scalability, signal to noise ratio scalability, and spatial scalability. We present results with a real video clip of 20 seconds duration, illustrating compression ratios of forty five hundred with acceptable (VHS type) quality. Due to the different nature and role played by the two types of GV data, we choose two transport protocols: TCP/IP for the transmission of the world images, and UDP/IP for the transport of the ancillary data. The paper describes the video system architecture and several design choice and optimizations that improve the overall performance of the video service.