Adaptation of portable base stations into cellular networks

#This description relates to directing packets among base stations and networks.

#Wireless devices such as cellular telephones, laptops, and Personal Digital Assistants (PDAs) are ubiquitous in today's culture of wireless communications and networking. Cellular wireless communications systems are designed to serve multiple wireless-enabled devices distributed over a large geographic area by dividing the area into regions called “cells”. At or near the center of each cell, a network-side access device (e.g., an access point) is located to serve client devices located in the cell and commonly referred to as “access terminals.” An access terminal generally establishes a call, also referred to as a “communication session,” with an access point to communicate with other entities (e.g., servers) in the network. Often the access terminals are mobile while the access points are stationary points of communication like cellular base stations. As wireless networking has moved into homes, businesses, vehicles, and other environments, local wireless access points have proliferated.

#In general the disclosure features methods for integrating a relatively large numbers of local wireless access points into, for example, a conventional cellular wireless communications systems, such a system being composed of stationary cellular base stations interfaced to a core network, in such a way that the behavior of the existing system need not be modified to accommodate the added population of local wireless access points. The method makes the access points in the aggregate appear as one or possibly just a few stationary cellular base stations.

#FIG. 1 illustrates an exemplary radio access network.

#FIG. 2 illustrates an exemplary radio access network that includes femtocell access points.

#FIG. 3 illustrates an exemplary radio access network that includes femtocell access points and a femtocell access point aggregator.

#FIG. 1 illustrates an exemplary cellular communications system. The radio access network (RAN) 104 includes stationary cellular base station 112 that includes a conventional antenna tower 102 that is erected at a fixed location and transmits and receives electromagnetic signals that are provided to and from a radio node (RN) 108. The RN 108 may support one or more of the wireless standards and protocols (e.g., CDMA-2000, UMTS, etc.) to establish communication links (via the antenna tower 102) with one or more mobile handsets (e.g., a mobile handset 106). The RN 108 may include a transceiver for receiving and transmitting electromagnetic signals. The RN 108 may also include various components (e.g., a modulator/demodulator (MODEM)) for modulating a transmission carrier signal to encode digital information for transmission or demodulating a received analog signal to decode transmitted digital information. The RN 108 is connected to a radio node controller (RNC) 110 that provides commands (and transmission signals) to the RN 108 and receives incoming signals from the RN 108. One or more stationary cellular base stations like 112 and 114 are controlled by a radio node controller 110. The radio node controller 110 is in communication with a mobile operator's core network 148 so that communication sessions can be established with other endpoints. For example, data may be sent to other base stations, conventional landline telephone systems (e.g., Plain Old Telephone Service (POTS) systems, etc.) or data networks. The core network 148 also performs other call control functions, mobility functions and high-level security functions. These functions include, for example, mobile handset location updating and authentication.

#FIG. 2 illustrates a cellular communications system that includes a stationary base station 212 and RNC 210 as well as a number of portable base stations referred to as femtocell access points (FAP) 216a, 216b, 216c. While the femtocells are typically used in residential applications, another type of portable base station is referred to as a picocell and is typically used in business applications. The FAPs 216a-c include respective antennas 230a-c, RNs 224a-c, RNCs 226a-c, and access gateways 228a-c. The FAPs 216a-c are capable of establishing communication links with one or more mobile handsets 206a-c. Typically, antenna characteristics (e.g., beam pattern, gain, etc.) of the FAP antennas 230a-c are selected for establishing links to mobile handsets located relatively close to the respective FAPs. Furthermore, design characteristics (e.g., component size, power consumption, etc.) of the FAPs 216a-c may be selected for portability. As such, the FAPs 216a-c may provide a smaller wireless coverage area (e.g., coverage to service a single residential home, a portion of a multiple residence building or other structure or location of similar size and area) than the fixed location base station 212. In this illustrated scenario, the FAPs 216a-c are placed in separate locations to establish communication links with respective mobile handsets 206a-c positioned local to the FAPs. By strategically placing the FAPs 216a-c, coverage can provided to mobile handsets in areas with little or no coverage from fixed base stations. For example, homes located along coastlines or in rural areas, campgrounds, mountain lodges, and island resorts may not be covered by commercial cellular services. In some deployments, the FAPs 216a-c may provide increased cellular network capacity in populated areas. For example, FAPs 216a-c may be permanently located in a densely populated office or apartment building, or they may be located temporarily to provide coverage during a sporting event or convention, or to provide coverage while a fixed base station is being repaired (e.g., for normal maintenance or after a natural disaster).

#The FAPs 216a-c are in communication with a mobile operator's core network 248 through a wide area network 214. In some implementations, the wide area network 214 may incorporate one or more hardwire and wireless transmission techniques (e.g., wire (copper), optical fiber, radio frequency (microwave), etc.). Along with public communication links (e.g., the Internet), the communication network 114 may use one or more private communication links (e.g., dedicated, T1, T3, E1), or a combination of public and private links. Private communications between the core network 214 and the FAPs 216a-c is facilitated by using a security gateway 246 so that communication through a virtual private network using encrypted tunnels between the FAP access gateways 228a-c and the security gateway 246 may be implemented.