Rashid Ahmed Akbar Attar

CDMA2000 1/spl times/EV-DO revision a: a physical layer and MAC layer overview

This article presents key enhancements to CDMA2000 1/spl times/EV-DO systems embodied in 1/spl times/EV-DO Revision A. These enhancements provide significant gains in spectral efficiency and substantial improvements in QoS support relative to 1/spl times/EV-DO Revision 0. In particular, 1/spl times/EV-DO Revision A approximately doubles the uplink spectral efficiency and doubles the number of terminals with delay-sensitive applications that can be simultaneously supported on the system. It provides substantial reduction in latencies (approximately 50 percent) during both connection setup and the connected state. It offers comprehensive network control over terminal and application performance to enable the desired trade-offs between capacity and latency/ fairness, thereby providing full QoS support and enhanced user experience. It also provides coverage improvement (approximately 1.5 dB) relative to 1/spl times/EV-DO Revision 0. This enables operators to offer services such as VoIP, video telephony, mobile network gaming, push-to-talk, Web browsing, file transfer, and video on demand to a larger number of simultaneous users. The 1/spl times/EV-DO Revision A network can provide downlink sector capacity of 1500 kb/s and uplink capacity of 500 kb/s (two-way receive diversity) or 1200 kb/s (four-way receive diversity) with 16 active users per sector, using just 1.25 MHz of the spectrum.

Evolution of cdma2000 cellular networks: multicarrier EV-DO

The evolution of cdma2000 1xEV-DO systems to multicarrier EV-DO (supported by 1xEV-DO Revision B) is discussed in this article. Multicarrier EV-DO offers a backward-compatible upgrade to leverage existing 1xEV-DO networks and terminals. It allows a software upgrade to multicarrier EV-DO using 1xEV-DO Revision A base station hardware. Multicarrier operation achieves higher efficiencies relative to single-carrier by exploiting channel frequency selectivity, improved transmit efficiencies on the reverse link, and adaptive load balancing across carriers. Multicarrier EV-DO enables very high-speed download, high-resolution video telephony, and improved user experience with concurrent applications. The sources of higher efficiency are discussed in detail in this article. It also enables hybrid frequency reuse deployment scenarios that enable spectrally efficient operation and significant improvement in edge coverage performance with hardware-efficient implementations. The evolved wider bandwidth systems (up to 20 MHz) based on multicarrier EV-DO offer operators a cost-effective solution that competes favorably with other technologies.

A reverse link outer-loop power control algorithm for cdma2000 1xEV systems

Reverse link outer-loop power control (ROLPC) algorithms developed for voice systems operate based on a continuous stream of packets (CRC events) to adjust the power control setpoint. Due to burstiness of data traffic a mechanism to distinguish between idle periods and data transmissions is necessary in systems optimized for data communications. In addition, such algorithms are unable to track changes in channel conditions during long idle periods. The proposed algorithm is designed to conservatively adapt to the channel in the absence of packets, with fast convergence at the start of a transmission. A parameterized algorithm is described with analysis and simulation results to justify baseline parameters. The performance of the algorithm for continuous and bursty TCP/IP traffic is presented.

On the reverse link performance of cdma2000 1/spl times/EV DO revision A system

cdma2000 1/spl times/EV-DO release 0 (DO ReL. 0), also known as IS-856, is a third generation (3G) wireless solution to providing wide-area high-speed mobile Internet access. cdma2000 1/spl times/EV-DO revision A (DO Rev. A) system provides enhancements to DO Rel. 0, such as higher spectral efficiency and advanced quality-of-service (QoS) support. In this paper we evaluate the reverse link performance of DO Rev. A system from a physical layer perspective. Specifically, we obtain DO Rev. A reverse link capacity via analysis as well as system simulations with complete modeling of physical- and MAC-layer dynamics. We show that DO Rev. A achieves significant capacity gain over DO Rel 0 in supporting delay-sensitive applications and provides flexible tradeoff in delay, capacity and physical-layer error-rate performance based on QoS requirement. Under moderate sector loading, DO Rev A achieves a reverse link sector capacity on the order of 600-700 kbps with two receiving antennas, i.e. a two-to-three fold improvement over DO Rel 0, while using the same 1.25 MHz of spectrum. Furthermore, sector throughput on the order of 1.2 Mbps is achievable with four receiving antennas, in the form of spatial array or pairs of cross-polarized (X-pol) antennas.

Reverse traffic channel MAC design of cdma2000 1xEV-DO revision A system

cdma2000 1xEV-DO (DO), also known as IS-856, is a third generation (3G) wireless solution providing high-speed mobile Internet access. cdma2000 1xEV-DO revision A (DO-RevA) system provides further enhancements to DO, such as higher system capacity and advanced quality-of-service (QoS) support In this paper we motivate and describe the design of the reverse link traffic channel MAC (RTCMAC) of DO-RevA system, which uses a novel combination of centralized specification of flow behavior together with autonomous mobile packet allocation subject only to resource congestion control. We demonstrate that RTCMAC achieves full resource allocation flexibility through an efficient robust design, well suited to the CDMA reverse link.

Interference Cancellation Techniques for CDMA2000 1x Reverse Link

Interference cancellation (IC) techniques yielding significant capacity gains are presented in this paper for CDMA2000 1x base station receiver. In addition to performance gain from conventional IC, hybrid ARQ gain is achieved effectively without interlaced transmission or feedback on the forward link (FL). A new definition of CDMA capacity, based on equivalent load, is introduced to allow a fair comparison of capacity with and without IC. Results from detailed simulations show that capacity gain for a typical commercial network will be between twofold and threefold, depending on spatial load distribution in the network. This capacity gain is achieved without any increase in voice latency or degradation to voice quality. It also does not require changes to the air interface or any handset replacement. The techniques proposed in this paper are applicable to base station receivers of other CDMA systems such as UMTS.

M2M over CDMA2000 1x case studies

In recent years, M2M (machine to machine) communications has increasingly been seen as a new growth area for wide-area wireless technologies which were designed for voice and high-speed packet data applications. In this paper, we use simulations to estimate the capacity of M2M applications over one of the widely used 3G wireless systems, CDMA2000 1x. We present capacity estimates of the CDMA2000 1x system for applications such as SMS, smart grid and vehicle tracking, under different network loading conditions. Our simulations show that the capacity of the aforementioned applications is reverse-link limited. In particular, the most commonly used configuration of reverse access channel in existing networks severely limits the M2M capacity. With better network configuration, use of enhanced access channel, and reverse link interference cancellation, the M2M capacity can be significantly improved. Our simulations show that the SMS capacity over 1x can reach about 2,400 SMSs per minute per sector on a single CDMA2000 1x carrier. In addition, the optimized network can support 56,000 smart-grid node or track approximately 2,900 vehicles per sector per 1.25MHz.

Repeaters and Remote Radioheads in EVDO Networks

This paper studies the different uses of repeaters and remote radioheads (fiber repeaters) in cellular networks. Traditional uses include coverage extension and eliminating points of pilot pollution (three-way handoff). In addition, we find that careful placement of repeaters can improve capacity substantially. We also find that in layouts where some sectors are much more heavily loaded than others, remote radioheads can be used to transfer load from heavily loaded to lightly loaded sectors, thereby improving network capacity. Therefore, repeaters can enhance network performance without changing either the software or the hardware of existing layouts.

Improving the Capacity of an Existing Cellular Network Using Distributed Antenna Systems and Right-of-Way Cell Sites

For an existing macro-cell wireless network deployment, it is shown how distributed antenna systems (DAS) can be added to improve the capacity. This is demonstrated through a set of experiments using a cdma2000 1xEV-DO outdoor test network on licensed spectrum with commercial reference devices and infrastructure equipment. DAS was used to add small cell sites at locations consistent with right-of-way deployments (e.g., light poles, traffic lights), and cell sites were added within both the interior and handoff regions of the existing macro network. For the case where the small cells were enabled as pico-cells, significant gains in capacity were found as a result of the cell- splitting and offloading of traffic demand onto the DAS sites, as well as the improved coverage within nearby buildings. Furthermore, when the smalls cells were configured to allow for centralized processing, additional performance gains were measured (1) when the downlink admits simultaneous transmission of pilot and data across remote sites, as well as for (2) when the uplink allows soft combining and interference cancellation across remote sites. These results were achieved using commercially available equipment at the DAS hub.

On Spatial Load Balancing in wide-area wireless networks

Load Balancing is typically used in cellular wireless networks in the frequency domain to balance paging, access, and traffic load across the available bandwidth. In this paper we extend the concept of Load Balancing to the Spatial domain. We develop two approaches - Network Load Balancing and Single-Carrier MultiLink - for Spatial Load Balancing. While these techniques are applicable to both cellular wireless networks and WiFi networks we illustrate them on EV-DO (a 3G cellular data network). Both these methods apply when the device has more than one candidate server and determine the server(s) using not only the channel quality from the server to the device but also the current load on each server. The proposed techniques leverage existing cellular (EV-DO) network architecture and are fully backward compatible. Network operators can realize both a substantial increase in network capacity and deliver a notable improvement in user experience by applying these techniques. The combination of load balancing in the frequency domain (Smart Carrier Management and multi-carrier) and spatial domain improves the connectivity within a network, enabling an optimal allocation of resources under the p-fair criterion.