Typically, standard local area network (LAN) protocols such as Ethernet provide access to network resources through wired, land line connections within a small geographic area (e.g., within an office building). However, until recently, LANs were limited to the conventional wired network connections. To increase mobility and flexibility, the concept of wireless LANs (i.e., WLANs) have been introduced. That is, WLANs provide convenient access to network resources for portable computers (e.g., a laptop computer) and handheld devices (e.g., a personal digital assistant (PDA)) both in and out of the office via an access point. In particular, the 802.11 communication protocol developed by the Institute of Electrical and Electronics Engineers (i.e., the IEEE 802.11 standard, IEEE std. 802.11-1997, published 1997) provides a standard for WLANs for wireless transmissions using spread spectrum radio frequency (RF) signals in the 2.4 gigahertz (GHz) Industrial, Scientific, and Medical (ISM) frequency band. The 802.11 communication protocol offers wireless transmission at rates of either one megabits per second (1 Mbps) or two megabits per second (2 Mbps) to access wired LANs. Based on the 802.11 communication protocol, the 802.11b communication protocol (i.e., IEEE 802.11b standard, IEEE std. 802.11b-1999, published 1999, which is also known as Wi-Fi or Wireless Ethernet) may extend the rate to 11 Mbps. The 802.11b communication protocol may also increase the RF coverage up to approximately 500 feet. Despite enhancing the ability of an electronic device to access a LAN (e.g., for web browsing and e-mail), the 802.11b communication protocol may not be optimal for establishing a wireless connection with devices in a wireless personal area network (WPAN) such as computers, cellular telephones, personal digital assistants (PDAs), and other peripherals such as a mouse. That is, a disadvantage of the 802.11b communication protocol is that a transceiver system (i.e., a radio system) operating in accordance with the 802.11b communication protocol may use an unnecessary amount of power to communicate with WPAN devices.
It is widely known that the Bluetooth communication protocol also uses short-range radio links to replace physical cables connecting between portable and/or fixed electronic devices. Like the 802.11b communication protocol, the Bluetooth communication protocol also operates in the unlicensed 2.4 gigahertz (GHz) ISM frequency band for short-range wireless connection between computers, cellular telephones, cordless telephones, PDAs, local area networks (LANs) and other peripherals such as a printer, a mouse, and a facsimile machine. In particular, the Bluetooth communication protocol may be used in wireless personal access networks (WPANs) because it requires less power than the 802.11b communication protocol. For example, a laptop notebook may be able to synchronize with a PDA, to transfer files with a desktop computer and/or another laptop notebook, to transmit or to receive a facsimile, and to initiate a print-out of a document. Thus, an advantage of the Bluetooth communication protocol is that the protocol is more robust to communicate with WPAN devices than the 802.11b communication protocol. However, a transceiver system operating in accordance with Bluetooth communication protocol may not be able to operate at sufficient power, range, and speed to access a LAN.
Accordingly, to provide short range ad-hoc connections between devices in WPANs and connections to WLANs, two transceiver systems operating in accordance with different communication protocols may be integrated into an electronic device. For example, a laptop notebook may include two transceiver systems with one transceiver system operating in accordance with the 802.11b communication protocol (i.e., 802.11b transceiver system) and the other transceiver system operating in accordance with the Bluetooth communication protocol (i.e., Bluetooth transceiver system). The 802.11b transceiver system uses a direct sequence spread spectrum (DSSS) modulation technique whereas the Bluetooth transceiver system uses a frequency hopping spread spectrum (FHSS) modulation technique. In particular, the DSSS modulation technique spreads data transmissions across 22 MHz segments of the entire available frequency band in a prearranged scheme. Within the 2.4 GHz frequency band, the 802.11b communication protocol defines 14 “center frequency channels” with channels 1 through 11 supported within the United States, and channels 12 through 14 supported outside the U.S. In particular, channel 1 at 2.412 GHz, channel 6 at 2.437 GHz, and channel 11 at 2.462 GHz being the more commonly used non-overlapping channels. Channels 1, 6, and 11 are spaced apart by 25 MHz. The 802.11b communication protocol may also be configured to provide six overlapping channels spaced 10 MHz apart. Typically, the DSSS modulation technique uses one channel and spreads data transmissions across a twenty-two megahertz band (i.e., a bandwidth of 22 MHz). Further, the 802.11 b transceiver system may encode data with a code known only to certain 802.11b transceiver systems so that data transmissions may not be as susceptible for intruders to intercept and decipher. With FHSS modulation technique, the Bluetooth transceiver system is synchronized to hop from channel to channel in a predetermined pseudorandom sequence known only to certain Bluetooth transceiver systems. The Bluetooth communication protocol includes up to 79 narrow channels with each channel having a one megahertz band (i.e., a bandwidth of 1 MHz in between 2.4 and 2.484 GHz). Typically, the FHSS modulation technique uses a majority of the channels and hops between the channels for data transmissions. As a result, the 802.11b transceiver system may be used for WLAN communication, and the Bluetooth transceiver system may be used for WPAN communication.
As noted above, however, both the 802.11b communication protocol and the Bluetooth communication protocol operate in the 2.4 GHz ISM frequency band. That is, the channels used by 802.11b transceiver system and the Bluetooth transceiver system may interference with each other. Thus, collision may occur when the 802.11b transceiver system and the Bluetooth transceiver system are communicating at the same time (e.g., the Bluetooth transceiver system may cause interference to the 802.11b transceiver system).
USPTO Backgrounds
USPTO Backgrounds