Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
2001-05-14
2004-09-14
Ton, Dang (Department: 2666)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
C370S442000
Reexamination Certificate
active
06791961
ABSTRACT:
BACKGROUND
The invention generally relates to wireless hybrid time division multiple access/code division multiple access communication systems. In particular, the invention relates to resource management in such systems.
FIG. 1
depicts a physical layout of a wireless communication system. The system has a plurality of base stations
20
. Each base station
20
communicates with user equipments (UEs)
22
in its operating area or cell
23
. Communications transmitted from the base stations
20
to the UEs
22
are referred to as downlink communications and communications transmitted from the UEs
22
to the base stations
20
are referred to as uplink communications.
A network perspective of a wireless communication system is shown in FIG.
2
. Each node-B
24
within the system wirelessly communicates with associated UEs
22
or users. Each node-B
24
has a single site controller (SC)
34
associated with either a single or multiple base stations
20
. A group of node-Bs
24
is connected to a radio network controller (RNC)
28
1
. To transfer communications between RNCs
28
, an interface between the RNCs (IUR)
26
is utilized. Each RNC
28
is connected to a mobile switching center (MSC)
30
which in turn is connected to the core network
32
.
In code division multiple access (CDMA) communication systems, multiple communications can be sent over the same spectrum simultaneously. The multiple communications are distinguished by their codes. In hybrid time division multiple access (TDMA)/CDMA communication systems, such as time division duplex (TDD) using CDMA (TDD/CDMA) communication systems, the spectrum is time divided into repeating frames having time slots, such as fifteen time slots. In such systems, communications are sent in selected time slots using selected codes. A physical channel is defined as one code in one time slot. The use of a single code in a single time slot with a spreading factor of sixteen is referred to as a resource unit. Based on the type of service being provided to a user (UE
22
) in the system, one or multiple physical channels may be assigned to support the users uplink and downlink communications.
The assignment of physical channels to users in such a system is a complex problem. Each physical channel used in a time slot creates interference with respect to other channels used in that time slot. Accordingly, it is desirable to choose time slots as to minimize interference.
However, there are drawbacks to choosing time slots solely based on interference. A UE
22
communicating using less time slots typically will have a lower power consumption. By stacking codes in a smaller number of time slots, other time slots are left open for new users. Additionally, some UEs
22
may be only able to use a few time slots, such as one or two.
Accordingly, it is desirable to have effective resource management in hybrid TDMA/CDMA communication systems.
SUMMARY
An order for physical channel reassignment is to be selected in a hybrid time division multiple access/code division multiple access wireless communication system. A fragmentation gauge is determined for each of a set of the physical channels. For each physical channel, the fragmentation gauge represents a fragmentation over time slots of that physical channel with respect to other physical channels of a user service of that physical channel. An order is selected for the set of physical channels for reassignment from a lowest to a highest quality. The order is based on in part each individual channel's fragmentation gauge.
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Zeira Eldad
Zhang Guodong
InterDigital Technology Corporation
Volpe and Koenig P.C.
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