1. Field of Invention
The present invention relates generally to operation within heterogeneous wireless systems such as, for example, hybrid network operation in which client devices can communicate using any one of several networks. More particularly, in one exemplary aspect, the present invention is directed to methods and apparatus for a network to minimize scheduling collisions with another network (e.g., one that is substantially unsychronized with the first network).
2. Description of Related Technology
A cellular network operator provides mobile telecommunications services to the public via a network infrastructure of e.g., cellular base stations (BS), base station controllers, infrastructure nodes, etc. There is a wide variety of cellular network technologies, and historically cellular devices have been specialized for operation within a single cellular network. However, as cellular technologies have become increasingly commoditized, devices are now able to offer so-called “multimode” operation; i.e., a single device that is capable of operation on two or more cellular networks. Multimode operation allows a device to operate on any one of several network technologies, but does not enable operation on multiple network technologies simultaneously.
Incipient research is directed to so-called “hybrid” network operation. During hybrid network operation, the client device operates simultaneously among multiple distinct networks having different technologies. In one exemplary ease, a hybrid device can support both: (i) Long Term Evolution (LTE) and (ii) Code Division Multiple Access 1× (CDMA 1×) networks; i.e., the device can maintain a simultaneous connection between a first LTE network and a second CDMA 1× network. For example, a LTE/CDMA 1× hybrid device can conduct a voice call over the CDMA 1× network while the mobile device is in LTE mode. In another exemplary case, a hybrid device can support both: (i) CDMA 1×-EVDO (Evolution Data Optimized) and (ii) CDMA 1× networks.
Existing solutions for hybrid network operation rely on the client device to manage its own operation between networks. Specifically, the client device is responsible for maintaining its active connections to the various service networks; there are no required changes to existing network installations (i.e., hybrid network operation does not affect the legacy hardware and software of the network infrastructure). Client-centric hybrid operation has several benefits. For example, there is very little (if any) infrastructure cost for the network operator. Moreover, hardware costs can be incorporated into the price of consumer devices. Additionally, hybrid network operation will not affect existing legacy devices. Similarly, devices capable of hybrid operation are also capable of normal operation.
However, since existing solutions for hybrid network operation do not require the constituent networks to coordinate with one another, the client device will inevitably experience certain scheduling collisions. For example, while a mobile device is attached to a first LTE network, it must periodically “tune out” the LTE network to perform CDMA 1× actions (such as decoding the Quick Paging Channel (QPCH) to determine if the device is being paged). If the mobile device is receiving data from the LTE network during the tune out period, this data is lost. Furthermore, a tuned out mobile device will miss any broadcasted updated network resource information or control data, this can result in the mobile device being barred from access to the LTE network (at least for a period of time).
Consequently, improved methods and apparatus are needed to minimize scheduling collisions for mobile devices.