METHOD AND SYSTEM FOR DYNAMIC
SOFT HANDOFF RESOURCE ALLOCATION
IN A WIRELESS NETWORK
RELATED APPLICATIONS 5
This application is a continuation of U.S. application Ser. No. 09/591,077 filed Jun. 9, 2000 now U.S. Pat. No. 6,907,243 and entitled "Method and System for Dynamic Soft Handoff Resource Allocation in a Wireless Network" 10 by Achal R. Patel.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/138,224 entitled "Method and Apparatus for Quality of Service (QoS) and Air Congestion Based Resource Allocation for Packet Delivery 15 Wireless Networks" filed Jun. 9, 1999, and which is hereby incorporated by inference.
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to the field of wireless communications, and more particularly to an improved method and system for dynamic soft hand off resource allocation in a wireless network.
BACKGROUND OF THE INVENTION
Wireline and wireless Internet Protocol (IP) networks have traditionally supported a best effort delivery of all traffic. However, current networks are optimized for real- 30 time voice services, despite the growing need for data services. Furthermore, the constraints imposed by voice and data traffic on the system are quite different. Voice transmissions must be in real time and are intolerant to delays. Large delays in the transmission of voice packets signifi- 35 cantly reduce the quality of the voice link. Also, network Grade of Service (GoS) requirements, such as probability of call blocking or outage and area reliability, as well as the treatment offered to all mobile voice users is the same. On the other hand, many data applications are tolerant to 40 reasonable delays without significantly impacting the link and application quality. Thus, quality of service requirements and the treatment required by different data applications are dissimilar.
To support enhanced services, multiple types, or classes, 45 of services have been established and assigned certain quality of service (QoS) parameters that manage queues for each service type. The QoS parameters include delay, jitter, error rates, and throughput. The QoS parameters can be provisioned on a per Internet Protocol (IP) connection or per 50 flow basis through mechanisms such as resource reservation protocol (RSVP) or can be provisioned on aggregate flow, which is classified into service classes. Internet service providers (ISPs) can utilize the service classes, their associated QoS behavior, and QoS provisioning to provide 55 multiple service offerings to their business and consumer customers.
As newer classes of services, with differing QoS requirements and different transmission characteristics are offered, it becomes imperative for wireless carriers to find new 60 methods and techniques to optimally utilize limited airbandwidth without affecting the overall network GoS. One attempt to ensure continual coverage, and thereby maintain QoS, is the "soft handoff." In modern wireless networks, Code-Division Multiple Access (CDMA) technology is used 65 to shares frequency across multiple users and applications. CDMA supports a soft handoff, in which a mobile user is
communicating with a mobile switching center via two or more cellular antennae sites and the user data is broadcast by all sites to the mobile user. This mode of communication makes the mobile-to-cell link resilient to obstructions in the beam path that can cause the active call to terminate abruptly. For the mobile to drop a call, the paths to all of the cells would have to be obstructed. A greater number of active links between the mobile and the network lowers the probability of dropping a call.
But, a mobile unit in soft handoff will cause all sites in handoff to transmit over a forward link to the mobile unit. This forward transmission from multiple sites to a single mobile unit, while improving the communication link to that particular mobile unit, increases the overall interference for other active mobile units in the system and can potentially degrade the performance of the forward link for all mobile units. Also, as the total forward power is limited, the available power for new users is considerably reduced. If several mobile units are in soft handoff at the same time, this can potentially lead to severe degradation in the overall system capacity.
SUMMARY OF THE INVENTION
The present invention provides an improved method and system for dynamic soft handoff and other macro diversity resource allocation in a wireless communications network that substantially eliminate or reduce problems and disadvantages associated with previous methods and systems. In particular, mobile users are characterized based on their relative impact on the network to manage the forward link interference caused by the mobile users in the soft handoff.
In accordance with one embodiment of the present invention, a method and system for allocating resources in a wireless network for macro diversity connections includes determining individual wireless path characteristics for each path of the macro diversity connection between a mobile device and a plurality of wireless sites. Wireless resources for the macro diversity connection are allocated between the mobile device and the wireless sites based on the wireless path characteristics.
The wireless path characteristics comprise location-based characteristics, interference-based characteristics, subscription-based characteristics and/or performance-based characteristics. The location-based characteristics include the location of the device along with related statistical information that allow the minimum resources needed from each site to meet subscriptions requirements to be determined. The interference-based characteristics include available bandwidth that allows intelligent allocation of resources to reduce air congestion and improved system capacity. The subscription-based characteristics include Quality of Service (QoS) that allow a fair distribution of resource in which higher level subscribers are provided more resources than lower level subscribers. The performance-based characteristics include real-time performance parameters to minimize redundancy and resource allocation.
Technical advantages of the present invention include providing an improved method and system for dynamic soft handoff and other macro diversity resource allocation in a wireless communications network. In particular, the active sets of mobile units communicating over wireless networks are biased to vary the resources allocated to a particular mobile unit. The bias values may be determined based on the geographic location (geo-location) of the mobile units, air congestion on the network, QoS subscriptions, link performance data, or any suitable combination of the above. This