Modern electronic devices, such as personal computers, notebook computers, netbook computers, cell phones, smartphones, mobile internet devices, and so on, utilize radio modules to communicate over wireless networks. Often, such devices may include two radio modules, for example, a wireless local area network (WLAN) radio module operating in compliance with an Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, and a personal area network (PAN) radio module operating in compliance with a Bluetooth protocol. Wireless local area networks are certified by the Wi-Fi Alliance, and are typically referred to as Wi-Fi networks. Alternatively, a wireless wide area network (WWAN), such as a Worldwide Interoperability for Microwave Access (WiMAX) compliant network or a Third Generation (3G) compliant cellular network may be used in combination with a Bluetooth (BT) network. Users of these devices typically will operate both radios simultaneously, for example, by streaming music to the device via the WLAN network and listening to the streamed music with Bluetooth connected headphones.
Due to channel adjacency, simultaneous operation of WLAN and Bluetooth radio modules may result in collisions on the transmission medium, thereby causing interference and/or packet loss. One of the common approaches to mitigate such issues is by using a media access control (MAC) coordination interface, often referred to as “coexistence interface,” that attempts to coordinate the operation of the two radios in a manner that minimizes collisions by partitioning the medium usage between radios. Current coexistence interfaces are typically designed as point-to-point interfaces to coordinate between two distinct radio technologies. Such designs may differ by the semantics of the signals in the interface, and/or by the behavior of the MAC layer or higher network layer. For example, a Bluetooth radio should behave differently when working with different types of radios, for example using different parameters for voice calls depending on the technology with which it cooperates.
Increasingly, mobile devices are incorporating three or more radios into a single device which should be designed to coexist in a similar manner as a two-radio device. As multiple radios are, however, combined into single modules, the pin count for a multiple radio interface may be greater than desired for a practical module. Typically, a two-wire interface may be utilized to implement a coexistence interface between two unique radio modules. Adding a third radio module would then involve a four-wire interface, thereby leading to a higher pin count, especially as additional radio modules are added. Furthermore, routing complexity may increase with additional wires used in the coexistence interface. When trying to reduce the number of pins, it may become a challenge to have different semantics on the wires between the two or more interfaces. As a result, the wires cannot be easily combined using simple logic gates or the like. An additional challenge is controlling the direction of the signals. While a Wi-Fi-BT coexistence interface may have two wires with two signals going in opposite directions, a WiMAX-BT coexistence interface may have two wires going from the WiMAX module to the BT module with two signals going in the same direction. This means if a Wi-Fi and WiMAX combination module were provided, to share a wire that functions in different directions, the correct timing between the Wi-Fi and WiMAX combination module and the BT module would have to be accommodated to ensure that the wire is never being driven at both ends simultaneously which might cause electrical malfunctions and/or render a module non-functional.
It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.