Patent Application
20080280630
The invention generally relates to wireless communications systems, and more particularly, to a novel and improved system and method for paging wireless mobile devices.
In recent years there has been an explosion of various wireless technologies such as WiFi (802.11), 3G (CDMA), WiMax (802.16) and many others. All of these technologies use different modulation schemes and access methods, such as code division multiple access (CDMA), orthogonal frequency division multiple access (OFDMA), or the like. To access network services using these different technologies, multi-mode mobile devices have been developed. Multi-mode devices are end-user devices configured to selectively interface to different wireless technologies. They allow users to connect to wireless communications networks irrespective of the underlying access technology.
Users of multi-mode wireless devices are mostly interested in network support for their particular applications, regardless of the underlying access technology. More importantly, users are interested in receiving uninterrupted services regardless of the access technology. Uninterrupted service is possible through a system design concept called seamless mobility. Seamless mobility provides the user with seamless access and connectivity across different wireless technologies and different wireless networks, such as wireless local area networks (WLANs), e.g., WiFi networks, and wireless wide area networks (WWANs), such as cellular phone networks.
Although WWAN air interface technologies such as GSM, cdma2000 and the like are designed to cover the regions surrounding their base stations (cells), not all areas within the intended coverage regions can receive WWAN service. These areas that lack coverage are typically known as coverage holes. WWAN coverage holes frequently occur inside buildings. To obtain wireless services within buildings or other coverage holes, multi-mode devices often connect to a WLAN providing coverage within the building or WWAN coverage hole. However, even though WLAN services may be available in some indoor environments, it is often desirable to continue receiving certain WWAN services within these coverage holes, sometimes because the WWAN service is simply not available from the WLAN or the equivalent WLAN service does not provide the features or level of quality desired by the multi-mode device user. WWAN paging is one such service. To improve user perception of seamless mobility, wireless mobile devices operating indoors or in other types of WWAN coverage holes should be able to receive WWAN pages. A possible solution is to improve WWAN technology so that WWAN pages are directly broadcasted over the WWAN, even to those users in coverage holes experiencing poor or no apparent WWAN coverage.
It is an advantage of the present invention to provide a system and method for successfully broadcasting pages over a WWAN into coverage holes, such as buildings, where WWAN services are not typically available. Wireless mobile devices actively operating on a WLAN are capable of receiving pages over WWAN. The ability to receive WWAN pages in areas where they are conventionally unavailable greatly enhances the value of WWAN paging service and can facilitate an improved user perception of the concept of seamless mobility.
Other advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.
It is to be understood that the drawings are solely for purpose of illustration and do not define the limits of the invention. Furthermore, the components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
The following detailed description, which references to and incorporates the drawings, describes and illustrates one or more specific embodiments of the invention. These embodiments, offered not to limit but only to exemplify and teach the invention, are shown and described in sufficient detail to enable those skilled in the art to practice the invention. Thus, where appropriate to avoid obscuring the invention, the description may omit certain information known to those of skill in the art.
For simplicity,
One or more wireless mobile devices 104 (e.g., cellular phones, personal digital assistants (PDAs) or the like) are included in the communications system 100 and are capable of radio communications with the WWAN through AN 102. The wireless mobile devices 104 can include multi-mode wireless devices capable of radio communications with both the WWAN AN 102 and the WLAN AP 112. The wireless mobile devices 104 actively operating on the WLAN are capable of monitoring and receiving WWAN page messages, as is described in further detail below.
The exemplary WWAN coverage region 106 contains three different types of radio channel environments: an indoor environment 108, an outdoor environment 110 and an outdoor-to-indoor environment. The indoor environment 108 is characterized by being located within a structure, such as a building. A structure may have permanent or temporary structures or elements, such as walls, within it. There may also be other objects as well. For example, a warehouse with no interior walls may be empty or it might be filled with cargo containers stacked to the ceiling. Some buildings and structures degrade or block radio signals. The outdoor environment is typically open space that may contain natural and man made structures. The outdoor-to-indoor environment is present when a radio signal is transmitted from the outdoor environment 110 to the indoor environment 108. The outdoor-to-indoor environment is typically encountered when the WWAN AN 102 attempts to page a wireless mobile device 104 that is located indoors within a building or other interfering structure.
In practice, these different channel environments occur in some WWAN coverage regions (cells). The presence of these different channel environments in a single coverage region can cause coverage holes. Principally, there are two causes of coverage holes: radio signal attenuation (including blocking) and fading. Within these coverage holes, WWAN paging service is typically not available to the wireless mobile devices 104. In addition, they can also cause dropouts when a wireless mobile device 104 moves from the indoor WLAN coverage area 114, where it is receiving wireless services through the WLAN, to the outdoor environment 110, where there is an inter-technology handoff from the WLAN to the WWAN.
To improve WWAN paging coverage, the WWAN AN 102 selectively varies the effective modulation order of a broadcast paging channel to achieve improved paging coverage within poor coverage regions, e.g., WWAN coverage holes. The WWAN preferably uses various orders of quadrature amplitude modulation (QAM), i.e., M-ary QAM, where M is a power of two. Described herein below are certain methods for varying the modulation order of the paging channel of the WWAN or for using layered modulation to variously modulate different components of the paging channel.
By broadcasting page messages at different modulation orders, the WWAN AN 102 allows the wireless mobile devices receiving WWAN pages, even while they are in indoor environments using the WLAN for data services or other services. This solution is particularly advantageous where the WLAN and WWAN operate in different frequency bands using different operators and/or air interface technologies.
The WWAN is preferably a cellular network such as a cdma2000, WCDMA, GSM, UTMS network or the like. The WWAN includes infrastructure comprising those network elements necessary to support wireless voice and data communications with the wireless mobile devices 104. The wireless communication infrastructure includes equipment such as controllers, transceivers and backhaul that establishes and maintains wireless communication with the wireless mobile devices 104, as well as other terminal devices. The types and amount of equipment within the wireless infrastructures depend on the particular wireless network. For example, a typical cellular network includes sector antennas connected to several base transceiver stations (BTSs) connected to base station controllers (BSCs) that are connected to a Mobile Switching Center (MSC). Cellular base station controllers are typically capable of communicating with an IP-based network, such as Internet, via a packet data server node (PDSN). Base stations are also capable of communicating with the public switched telephone network (PSTN) via the MSC. Thus, conventional cellular base stations included in the WWAN use the MSC and PSTN to provide conventional voice connections and telephony services between the wireless mobile devices 104 and other telephone devices over the WWAN. In addition, base stations of the WWAN use a PDSN and the Internet to provide packet data services, such as voice-over-IP (VoIP) and short messaging service (SMS), between the wireless mobile devices 104 and Internet protocol (IP) nodes communicating with the WWAN.
For seamless mobility of voice communication, VoIP may be provided by both the WLAN and WWAN. In this type of communications system, the AN may replace the BTS, and a PCF (Packet Call Function) could replace the BSCs in the WWAN. The PCF would connect directly to the PDSN.
In certain WWANs, an IP multimedia subsystem (IMS) serves as the core network. The IMS can support both the WWAN and WLAN to provide seamless handoffs between the two technologies. Specifically, the WLAN can be connected to the IMS via an IWF (interworking function), which is controlled by the cellular carrier.
In addition, in WWANs using Unlicensed Mobile Access (UMA) Technology, GSM and GPRS mobile services are available over WiFi. The WiFi network is connected to the cellular core network through the IP access network and a UMA network controller.
The WLAN is preferably a packet-based network, such as a WiFi network (e.g., IEEE-802.11a/b/g/n), that supports a peer-to-peer protocol between those wireless mobile devices 104 that feature multi-mode capabilities. The WLAN includes those network elements necessary to support data and voice communications with the wireless multi-mode devices. For example, the WLAN may support voice-over-IP (VoIP) service over the WiFi connections.
Although the present invention is not limited to any particular implementation of the WWAN AN 102, the WWAN AN 102 is preferably a cellular base station, as described above, that is connected to or includes at least one antenna 201, and includes a processor 202, a memory 204 and an air interface with a radio frequency transceiver 206 having a transmitter (Tx) 208 and a receiver (Rx) 210 for communicating with the wireless mobile devices 104. The processor 202 is configured to perform in accordance with at least one the paging methods described herein, and may perform other baseband processing of digitized information. This processing typically comprises modulation and demodulation, encoding and decoding, interleaving and de-interleaving, multiplexing, error correction operations and the like. As such, the processor 202 is generally implemented in one or more digital signal processors (DSPs) and/or application specific integrated circuits (ASICs). The memory 204 stores one or more software programs executed by the processor 202 to perform its functions.
The AN 102 may be implemented with other architectures. For example, the transceiver 206 and/or antenna(s) 201 may be located outside of the AN 102, with the AN 102 connected thereto.
Each wireless mobile device 104 includes at least one antenna 219, a processor 220, a memory 222 and an air interface with radio frequency transceiver 224 having a transmitter (Tx) 226 and a receiver (Rx) 228 for communicating with the WWAN AN 102. Those wireless mobile devices 104 having multi-mode capabilities also include an additional air interface and transceiver from communicating with the WLAN AP 112. The processor 220 is configured to extract page messages broadcasted by the WWAN AN 102 according to one or more of the methods described herein. The processor 220 may also perform other baseband processing of digitized information. This processing typically comprises modulation and demodulation, encoding and decoding, interleaving and de-interleaving, multiplexing and de-multiplexing, error correction operations and the like. As such, the processor 220 is generally implemented in one or more digital signal processors (DSPs) and/or application specific integrated circuits (ASICs). The memory 222 stores one or more software programs executed by the processor 220 to perform its functions.
In step 254, the AN 102 selects a page channel modulation order based on a request from the wireless mobile device 104. The request can indicate the signal strength detected by the wireless mobile device 104. The wireless mobile device 104 can transmit the request indicating the signal strength to the AN 102 on a reverse control link. The modulation order and other related parameters can be negotiated between the wireless mobile device 104 and the AN 102 as soon as a change in signal strength is detected, such as going from good signal strength to poor signal strength, or visa versa. The request for modulation order can additionally or alternatively be incorporated into any access attempt or access message from the wireless mobile device 104 to the WWAN, including a registration message or L2 response.
Although any suitable modulation order or number of modulation orders may be used, the default modulation order for the paging channel may be set to 16-QAM for users in outdoor environments or otherwise in good coverage regions.
If the detected signal strength is low (e.g., the wireless mobile device 104 is within the indoor environment 108) the wireless mobile device 104 requests to the AN 102 that any page message sent on the paging channel be sent in a lower-order modulation for higher robustness (e.g., QPSK instead of 16-QAM).
The modulation order request sent by the wireless mobile device 104 in step 254 can also be used to adjust the robustness of a quickpaging channel (QPCh). The QPCh carries a single bit indicating the presence of a page. Typically, to make the QPCh robust, it is either repeated multiple times or transmitted at a higher power-level by the AN 104. When the wireless mobile device 104 requests a certain modulation order, it provides an indication for the AN 102 to configure the parameters for the QPCh. In this case, the parameters are either the number of repetitions or/and the power-level to be used for QPCh. If the request is for a lower-order modulation, the QPCh parameters are adjusted by the AN 102 to relatively increase the QPCh transmission repetitions and/or power level; whereas a request for higher-order modulation results in a relative decrease in QPCh transmission repetitions and/or power level.
In step 256, the AN 102 modulates the page message using the selected modulation order. In step 258, the AN 102 broadcasts the modulated page message on the paging channel to the recipient wireless mobile device 104. The wireless mobile device then demodulates the page message using the selected modulation order. Since the page message has the same content regardless of whether it is modulated using QPSK, 16-QAM, the paging slot would be twice as long for QPSK when compared to 16-QAM. Therefore, wireless mobile devices 104 requesting QPSK modulation or other lower-order modulations would need to turn on their receivers 228 for longer durations to monitor pages in their slot cycle than wireless mobile devices 104 operating in good channel environment using 16-QAM.
If the page is received successfully, the traffic channel can also use the selected modulation order to transmit the contents of the voice or data packets to the wireless mobile device 104 in a poor coverage region.
For some wireless mobile devices operating in poor coverage, it is possible that the page messages may not be received successfully, even though such wireless mobile devices can successfully send control messages, such as page acknowledgements (ACKs), on the reverse link. This is because the gain on the paging channel broadcasted by the AN is typically fixed regardless of the location of the wireless mobile device. However, for control messages on the reverse link, e.g., page ACKs, the wireless mobile device has the option to boost up its transmission signal strength to compensate for poor coverage (up to Pmax).
In other poor coverage situations, it is possible that some wireless mobile devices may not be able to send page ACKs back to the AN, even it if they did receive page messages successfully. In the case when a wireless mobile device receives a page successfully or when the wireless mobile device receives only the page message using the lower modulation order, but cannot ACK the page due to reverse link limitations, the wireless mobile device can indicate to the user that a page has been received (including the calling party number), but that the call completion was unsuccessful. This user indication is applicable in all of the paging methods described herein.
The method of
In step 272, the AN 102 divides the paging channel itself into the base channel and the extended channel. An entire page message is transmitted by the AN 102 on either the base paging channel or the extended paging channel, depending on the logical channel selected for the recipient wireless mobile device 104. Each of these channels is independently encoded and interleaved by the AN 102. Any other pre-modulation processing on the base and extended channels is also performed independently.
The AN 102 determines the appropriate page messages to be grouped together to form the base and extended message pairs for the layered modulation. If pages are needed for only one type of channel environment, i.e., the wireless mobile devices 104 request only the base channel or extended channel, but not both, the non-requested paging channel can carry other data or fill data. If only the base channel has paging data to be sent and there is only fill data on the extended channel, the modulation symbols in the QAM constellation representing the base channel data may be selected to achieve the greatest distance, on average, from the symbols in the other quadrants.
Initially, the AN 102 may assign a wireless mobile device 104 to a default logical paging channel, either the base channel or the extended channel, unless otherwise negotiated. The default paging channel does not have to be the same for all of the wireless mobile devices 104. The default paging channel may be negotiated during registration of the wireless mobile device 104 on the WWAN, for example. The request for a particular logical paging channel can be incorporated into any access attempt or access message from the wireless mobile device 104 to the AN 102, including a registration message or L2 response.
A wireless mobile device 104 may switch from extended to base channel, and visa versa, whenever warranted by channel conditions. There are several ways of determining when to switch between base and extended paging channels. As shown in decision step 274, a wireless mobile device 104 can maintain common channel error rates for other channels, such as a broadcast message control channel or the base and extended components of overhead message control channels, as described in the Related U.S. patent application No. ______, filed ______, entitled “System and Method for Broadcasting Overhead Parameters in Poor Coverage Regions”, Attorney Docket No. TUTL 00136. Depending on the common channel error rates, the wireless mobile device 104 may assign crossover points as trigger points to request the WWAN AN 102 to send page messages over either the base or the extended channel. For example, if the common channel error rate exceeds a threshold (e.g., a trigger point), the AN 102 encodes, interleaves and processes the outgoing page message onto the base logical channel, which uses a lower-order QAM modulation to improve robustness (step 276). If, on the other hand, the common channel error rate is less than the threshold, the AN 102 encodes, interleaving and processes the outgoing page message onto the extended logical channel, which uses a higher-order QAM modulation for reception in good coverage areas (step 278).
Alternatively, the wireless mobile device 104 can detect when it first acquires or loses WLAN service and then switch paging channels at that time. When a wireless mobile device 104 first acquires a WLAN, this situation usually indicates that the wireless mobile device 104 is about to move from a good coverage area into a coverage hole. Typically, when the WLAN is first acquired (e.g., at the entry of a building), WWAN services are still available; and therefore, at this particular time, requests to the WWAN AN 102 can still be completed successfully. It is at this particular time that a wireless mobile device 104 can send a request to the AN 102 to switch from the extended paging channel to the base paging channel. Conversely, when the wireless mobile device 104 first detects loss of the WLAN, it can request the AN 102 to switch back to the extended paging channel.
In step 280, the base and extended channels are multiplexed together and layer modulated using layered QAM, as described in further detail herein in connection with
In step 284, the layer-modulated page message is broadcast by the AN 102 to the recipient wireless mobile device 104.
The request sent by the wireless mobile device 104 to switch between the base and extended paging channels can also be used to adjust the robustness of a quickpaging channel (QPCh). The QPCh carries a single bit indicating the presence of a page. Typically, to make the QPCh robust, it is either repeated multiple times or transmitted at a higher power-level by the AN 104. When the wireless mobile device 104 requests a certain logical paging channel, it provides an indication for the AN 102 to configure the parameters for the QPCh. In this case, the parameters are either the number of repetitions or/and the power-level to be used for QPCh. If the request is for the base channel, the QPCh parameters are adjusted by the AN 102 to relatively increase the QPCh transmission repetitions and/or power level; whereas a request for the extended channel results in a relative decrease in QPCh transmission repetitions and/or power level.
In step 302, the AN 102 divides a page message into base and extended components. The page message can be divided into the components in equal proportions, or any other suitable proportion. The base component may include at least the minimum information required by the recipient wireless mobile device 104 to complete the page process.
In step 304, the AN 102 constructs the base and extended components into two separate logical channels: the base channel and the extended channel. Each of these channels is independently encoded and interleaved by the AN 102. Any other pre-modulation processing on the base and extended components is also performed independently.
In step 306, the AN 102 multiplexes and then modulates the two logical channels using layered modulation. Layered quadrature amplitude modulation (QAM) is preferably used. Layered modulation supports the division of page messages into two logical channels. Using layered modulation allows the wireless mobile devices 104 to demodulate the base component under poor channel conditions. Layered modulation also allows the use of the same physical packet format (i.e., the same packet length, cyclic-preamble for OFDM, and so forth) to serve multiple wireless mobile devices 104 in different channel environments. Thus, wireless mobile devices 104 in good coverage conditions (e.g., the outdoor environment 110) can demodulate both the base and the extended components with relatively ease. Further details of the layered modulation performed by step 306 are described below in connection with
Typically in the outdoor-to-indoor environment, the wireless mobile device 104 is able to receive enough energy from the WWAN AN 102 to detect a pilot channel used for synchronization and channel estimation. However, the wireless mobile device 104 may not receive sufficient signal energy to fully demodulate the WWAN paging channel. Splitting the paging channel into the base and extended components and applying layered modulation to these components allows the wireless mobile device 104 to demodulate the critical base component at a much lower received signal level.
In step 308, both base and extended components are broadcasted on the paging channel by the WWAN AN 102 to the wireless mobile devices 104.
The method of
In step 354, the wireless mobile device 104 determines whether the signal strength is strong enough so that it can successfully demodulate both the base component and extended component channels. If the device 104 is capable of successfully demodulating both page component channels, it proceeds to extract the entire page message from the page channel. The device then sends a page acknowledgement (ACK) to the AN 102 with an indication bit LAYER_MOD set to ‘1’ to indicate that the entire page message was correctly received.
However, if the device cannot demodulate both the base and extended components, the wireless mobile device 104 determines whether it can successfully demodulate only the base component channel (step 356).
Further details of decision steps 354 and 356 are described below in connection with
If the received signal strength is too weak to permit the wireless mobile device 104 to demodulate even the paging channel's base component, the device 104 does not send a page ACK to the AN 102, and continues to monitor the paging channel for subsequent pages.
If the signal strength is strong enough to permit demodulation of only the base component, but not the extended component, the wireless mobile device 104 proceeds to demodulate and extract the base component of the page message. In step 360, the device 104 then sends a page ACK to the AN 102 with the indication bit LAYER_MOD set to ‘0’ to indicate that only the base component of the page message was correctly received.
In step 362, the AN 102 determines whether the maximum number of pages has been sent to the recipient wireless mobile device 104. If so, the AN 102 discontinues paging the device 104 for the current page message. If not, the AN 102 processes the extended component of the page message onto the base component channel and sends a second page message to the device 104 with the base component essentially swapped with the extended component (step 364). To prevent possible confusion, the page message may include an indication bit to inform the wireless mobile device 104 that the current page message content has been swapped.
In step 366, the wireless mobile device 104 determines whether it has successfully demodulated the base component of the second page message. If not, the process returns to step 362, and the AN 102 may attempt to re-send the second page message, if the maximum number of pages has not been exceeded. If demodulation of the second page message is successful, the device 104 sends a page ACK to the AN 102 with the indication bit LAYER_MOD set to ‘1’ to indicate that the entire page message was correctly received (step 368).
Using the third paging method, a recipient wireless mobile device 104 in good coverage conditions can successfully demodulate the extended and base components (16-QAM modulated paging channel) with no error. If the device 104 is in poor coverage conditions and only the base component can be demodulated successfully, the wireless mobile device 104 saves the base component page message content and sends an indication in the form of an ACK to the WWAN AN 102 that only the base component is successfully demodulated. After the AN 102 receives the ACK with the indication, the AN 102 re-transmits the page message to the device 104 with the exception that the portion of the page message previously sent on the extended component is now sent over the base component. The device 104 receives the second page and is able to demodulate the base component comprising page message information not successfully demodulated in the first page attempt.
The third paging method has several advantages. The first advantage is that only wireless mobile devices 104 experiencing poor channel environments need to monitor successive page messages. In addition, the wireless mobile devices 104 in good coverage areas do not need to wake up for a longer duration to listen to page messages just to support wireless mobile devices 104 in poor coverage areas. Furthermore, the third method does not require that the recipient wireless mobile device 104 inform the AN 102 whether the page message should be sent on the base or the extended component. Additionally, since only one page message is sent in the paging slot using layered modulation that is formed by the base and extended components, a wireless mobile device 104 in good coverage conditions would need to wake up for only half the time to monitor paging messages as compared to the second method described above in connection with
For all of the above methods, the recipient wireless mobile device 104 may send a page ACK to the AN 102 in one of several ways. First, the page ACKs can be transmitted using the WWAN traffic uplink. Typically, reverse-link control channels have a more robust air-link than the reverse-link traffic channel. This is done to provide reliable feedback to the AN 102 so that the AN 104 can adapt to provide efficient performance. With more robust encoding and modulation, ACKs transported on the reverse-link channels are more reliable.
Second, the page ACKs can be transmitted through the WLAN, if the wireless mobile device 104 is in a WLAN coverage area 114. To send page ACKs through the WLAN, the WLAN is connected to the WWAN's IP multimedia subsystem (IMS). This could also be an indication that the user prefers to have that particular service on WLAN if paged.
The encoders 500, 504 and interleavers 502, 506 provide error correction processing. The encoders 500, 504 may employ any suitable error correction coding, such as turbo coding, and the interleavers 502, 506 may employ any suitable interleaving algorithm.
As shown in
To additionally improve reception of the base components, the AN 102 can also adjust the energy level of the 16-QAM modulation symbols, as shown in
Alternatively, the wireless mobile device 104 may monitor broadcasted signal strength and attempt to recover a page message without a threshold comparison. In this case, the wireless mobile device 104 demodulates both the base and extended components at all times. The base and extended components may indicate successful recovery of the page message depending on the outcome of error checking, e.g., the CRC (cyclic redundancy check) or equivalent, for each of the components.
The channel estimator 914 provides a signal strength, C/I, to the threshold comparator 916, which determines the QAM modulation order to be used by the layered demodulator 918. The threshold comparator 916 can include one or more look-up tables (LUTs) to store signal-to-noise ratio (SNR) ranges and corresponding modulation order values and/or code-rate. The LUTs for the SNR may be updated depending on the relative levels of the pilot gain (Gp) and the gain used in the base logical component, since the pilot level transmitted may change depending on traffic conditions. If the threshold comparator 916 indicates that SNR is sufficient, both base and extended components can be demodulated successfully using the 16-QAM demodulator.
However, if the threshold comparator 916 indicates a low SNR, it is possible that only the base component can be successfully demodulated. In this case, for each received 16-QAM symbol, the layered demodulator 918 only needs to determine in which quadrant the symbol has the least probability of error. Instead of choosing among the sixteen possible 16-QAM symbols, the layered demodulator 918 only needs to make a decision based on four possible outcomes (similar to QPSK demodulation). This is possible because the modulation symbol for each quadrant does not change with respect to the base component bits.
Although a particular communication system 100 is specifically described above, the methods and systems described herein are applicable to any suitable communications system architecture or air interface technology (e.g., CDMA, OFDMA, and the like). Basic radio system parameters and call processing procedures for exemplary CDMA WWAN systems that can incorporate the systems and methods described herein are described in a TIA specification, entitled “Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System,” TIA/EIA/IS-95-A, published in May 1995 by the Telecommunications Industry Association, and referred to hereafter as “IS-95A”. The update and revision to IS-95A and J-STD-008 (PCS specification analogous to IS-95A) is TIA/EIA/IS-95-B, first published in March 1999 by the TIA and referred to hereafter as “IS-95B”. The IS-95A and IS-95B specifications are jointly known as second generation or “2G” CDMA system specifications. A third generation or “3G” CDMA system is described in the TIA specification, entitled “cdma2000 Series”, TIA/EIA/IS-2000-A, first published in March 2000 by the TIA, and referred to hereafter as “IS-2000”. Other TIA air interface specifications for the cdma2000 family of standards include TIA-856 entitled “cdma2000 High Rate Packet Data Air Interface Specification” as well as TIA-1121 entitled “Ultra Mobile Broadband Air Interface Specification. The IS-95A, IS-95B, IS-2000 and other TIA specifications mentioned above, and their updates are hereby incorporated by reference for their teachings on CDMA communication systems.
Other embodiments and modifications of this invention will occur readily to those of ordinary skill in the art in view of these teachings. The above summary and description is illustrative and not restrictive. The invention is to be limited only by the following claims, which include all such embodiments and modifications when viewed in conjunction with the above specification and accompanying drawings. The scope of the invention should, therefore, not be limited to the above summary and description, but should instead be determined by the appended claims along with their full scope of equivalents.
This application is related to U.S. patent application No. ______, filed ______, entitled “System and Method for Broadcasting Overhead Parameters in Poor Coverage Regions”, having Attorney Docket No. TUTL 00136, and assigned to the assignee of the present application, the disclosure of which is fully incorporated herein by reference in entirety.
