Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
2002-03-11
2004-12-21
Tran, Congvan (Department: 2685)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S067110, C455S525000, C455S456500, C370S332000, C370S333000
Reexamination Certificate
active
06834194
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, generally, to communication network management and, in one embodiment, to a method and apparatus for generating and utilizing a relative future activity indicator for selecting the source of received communications.
2. Description of Related Art
Introduction
Cellular communication networks are rapidly becoming a primary infrastructure for enabling communication in today's society. In addition to providing a means for voice communications such as personal or business telephone calls, cellular communication networks are now being used for transmitting data. As demand for cellular communications has increased, cellular communication networks are becoming increasingly prevalent and are providing coverage over larger areas to meet consumer demand.
FIG. 1
illustrates an example system environment including a mobile station (MS)
10
capable of maintaining a connection
30
with a cellular communication network
22
as the MS
10
roves through a geographic area served by the cellular communication network
22
. It should be understood that a connection, as referred to herein, includes, but is not limited to, voice, multimedia video or audio streaming, packet switched data and circuit switched data connections, short message sequences or data bursts, and paging. The cellular communication network
22
includes a first base station (BS)
12
communicating over sectors
14
and
16
, and a second BS
18
communicating over sector
20
. A BS is typically comprised of multiple sectors, usually three. Each BS includes a separate transmitter and antenna (transceiver) for each sector, pointed in the direction of the sector. Because a BS can be omni or sectorized, it should be understood that the terms BS and sector may be used interchangeably herein. Furthermore, when referring to access to a network via a network access point, the terms BS, sector, and network may be used interchangeably herein. The BSs are connected to network infrastructure entities including BS controllers (BSC)
24
that may control a cell cluster
26
, and communicate with a mobile switching center (MSC)
28
. It should be understood that the MS
10
, BSs and one or more of these network infrastructure entities may contain one or more processors for controlling communications between the MS
10
and the network
22
. The processors include memory and other peripheral devices well understood by those skilled in the art.
In the course of roving, MS
10
travels from position A to position B to position C and will, as a matter of course, experience variations in signal strength and signal quality of the communication link associated with the BS(s) that it is in contact with. Signal strength and quality can be especially undependable near the edges of the sectors, such as when the MS
10
transitions from the area defined by the dotted line of sector
14
to the area defined by the dotted line of sector
16
, or from sector
16
to sector
20
.
Cellular Communication Links
FIG. 2
illustrates an exemplary communication link
30
between a MS
10
and a BS
12
. Communications from the BS
12
to the MS
10
are called the forward link, and communications from the MS
10
to the BS
12
are called the reverse link. The forward and reverse links utilize a number of forward and reverse channels. For example, the BS
12
communicates with the MSs using a plurality of forward common channels or links which may include, but are not limited to, one or more pilot channels, a sync channel, and one or more paging channels, discussed in greater detail below. These channels are referred to as common channels because the BS
12
may communicate those channels to all MSs in the network. Generally, these common channels are not used to carry data, but are used to broadcast and deliver common information.
Each sector within BS
12
broadcasts a pilot channel that identifies that sector and is simple for a MS
10
to decode. Both sectors and pilot channels are distinguished by pseudo-noise (PN) offsets. The word “pilot”can be used almost interchangeably with the term sector, because a pilot channel identifies a sector. The pilot channel implicitly provides timing information to the MS, and is also used for coherent demodulation, but it otherwise typically does not contain any data. When a MS is first powered up, it begins searching for a pilot channel. When a MS acquires (is able to demodulate) a pilot channel, the timing information implicit in the pilot channel allows the MS to quickly and easily demodulate a sync channel being transmitted by the network.
Because the sync channel contains more detailed timing information, once the MS acquires the sync channel, the MS is then able to acquire a paging channel being transmitted by the same BS that is transmitting the pilot channel. That BS is known as the active BS. When a cellular network is attempting to initiate communications with a MS through a particular BS, a “page”is transmitted to that MS on the paging channel of that BS. Thus, once the MS is able to demodulate the paging channel of a particular BS, the MS may then monitor that paging channel while the MS is idle and waiting for incoming connections or an incoming message. In general, each BS may utilize one pilot channel, one sync channel and one paging channel that are common for all MSs to receive. However, because there are practical limitations on the number of MSs that can be simultaneously paged using one paging channel, some BSs may employ multiple paging channels.
In addition to the forward common channels described above, the BS
12
communicates with individual MSs using a plurality of forward dedicated channels or links which may include, but are not limited to, multiple traffic channels, multiple supplemental channels, and multiple access channels and control channels. These channels are referred to as dedicated channels because the BS communicates the channels to a specific MS
10
, and the channels may carry data.
The reverse channels or links may include an access channel and one or more reverse traffic channels and control channels. After a MS receives an incoming page from a BS, the MS will initiate a connection setup using, in part, an access channel.
Cellular Network Communication Schemes
The previously described channels may employ different coding schemes. In time division multiple access (TDMA), multiple channels may be communicated at a particular frequency within a certain time window by sending them at different times within that window. Thus, for example, channel X may use one set of time slots while channel Y may use a different set of time slots. In frequency division multiple access (FDMA), multiple channels may be communicated at a particular time within a certain frequency window by sending them at different frequencies within that window.
Code division multiple access (CDMA) is a technique for spread-spectrum multiple-access digital communications that creates channels through the use of unique code sequences. It allows a number of MSs to communicate with one or more BSs in neighboring cell sites, simultaneously using the same frequency. In CDMA, given a space of frequency and time, each channel is assigned a particular orthogonal code such as a Walsh code or a quasi-orthogonal function (QOF). In direct sequence CDMA, the data from each channel is coded using Walsh codes or QOFs and then combined into a composite signal. This composite signal is spread over a wide frequency range at a particular time.
When this composite signal is de-spread using the same code used to spread the original data, the original data may be extracted. This recovery of the original data is possible because Walsh codes and QOFs create coded data that, when combined, don't interfere with each other, so that the data can be separated out at a later point in time to recover the information on the various channels. In other words, when two coded sequences of data are added together to produce a third sequence, by correlating that t
Denso Corporation
Morrison & Foerster / LLP
Tran Congvan
LandOfFree
Relative future activity indicators for assisting in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Relative future activity indicators for assisting in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Relative future activity indicators for assisting in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3327160