1. A pipe assembly for containing and transporting cryogenic temperature fluids comprising:
a) at least one inner pipe;
b) a composite overwrap that at least partially surrounds the at least one inner pipe, wherein the composite overwrap is capable of enduring exposure and stress at cryogenic temperatures and has a near zero or negative coefficient of thermal expansion, wherein the composite overwrap is bonded to the inner pipe along an axial direction defined by the inner pipe to form a combined composite overwrap and inner pipe, wherein the combined composite overwrap and inner pipe is characterized by an overall coefficient of thermal expansion near zero; and
c) an outer pipe that at least partially surrounds the combined composite overwrap and inner pipe so as to define an annular space between the exterior surface of the combined composite overwrap and inner pipe and the interior surface of the outer pipe, wherein the annular space between the outer pipe and the combined composite overwrap and the inner pipe is provided with thermal insulation.
2. The pipe assembly according to claim 1, wherein the assembly is selected from the group consisting of: multiple external pipes, pipe-in-pipe assembly, and pipe-in-pipe-in pipe assembly.
3. The pipe assembly according to claim 1, wherein the inner pipe is made of a material selected from the group consisting of: austenitic stainless steel, grade 304 stainless steel, and grade 316 stainless steel.
4. The pipe assembly according to claim 1, wherein the inner pipe is made of a material selected from the group consisting of: grade 304 stainless steel, grade 316 stainless, and grade 9 percent nickel alloy.
5. The pipe assembly according to claim 1, wherein the composite overwrap is bonded to the inner pipe utilizing mechanical locking via weld beads.
6. The pipe assembly according to claim 1, wherein the composite overwrap is bonded to the inner pipe utilizing residual stresses is accomplished by an autofrettage pressure cycle.
7. A pipe assembly for containing and transporting cryogenic temperature fluids comprising:
a) at least one inner pipe wherein the at least one inner pipe is made of material resistant to cryogenic temperatures;
b) a composite overwrap capable of enduring exposure and stress at cryogenic temperatures having a near zero or negative coefficient of thermal expansion, wherein the composite overwrap is bonded to the inner pipe in an axial displacement forming a combined composite overwrap and inner pipe; and
c) an outer pipe that at least partially surrounds the combined composite overwrap and inner pipe so as to define an annular space between the exterior surface of the combined composite overwrap and inner pipe and the interior surface of the outer pipe.
8. The pipe assembly according to claim 7, wherein the assembly is selected from the group consisting of: multiple external pipes, pipe-in-pipe assembly, and pipe-in-pipe-in-pipe assembly.
9. The pipe assembly according to claim 7, wherein the inner pipe is made of material capable of assisting in achieving near zero or negative coefficient of thermal expansion.
10. The pipe assembly according to claim 7, wherein the inner pipe is made of a material selected from the group consisting of: austenitic stainless steel, grade 304 stainless steel, and grade 316 stainless steel.
11. The pipe assembly according to claim 7, wherein the composite overwrap is bonded to the inner pipe utilizing mechanical locking via weld beads.
12. The pipe assembly according to claim 7 , wherein the composite overwrap is bonded to the inner pipe utilizing residual stresses is accomplished by an autofrettage pressure cycle.
13. A pipe assembly for containing and transporting cryogenic temperature fluids comprising:
a) at least one inner pipe wherein the at least one inner pipe is made of material resistant to cryogenic temperatures;
b) a composite overwrap capable of enduring exposure and stress at cryogenic temperatures having a near zero or negative coefficient of thermal expansion, wherein the composite overwrap is bonded to the inner pipe in an axial displacement forming a combined composite overwrap and inner pipe by utilizing at least one of: laminate plate theory and optimization software to satisfy the near zero or negative coefficient of thermal expansion, adhesive bonding, and residual stresses; and
c) an outer pipe that at least partially surrounds the combined composite overwrap and inner pipe to define an annular space between the exterior surface of the combined composite overwrap and inner pipe and the interior surface of the outer pipe.
14. The pipe assembly according to claim 13, wherein the assembly is selected from the group consisting of: multiple external pipes, pipe-in-pipe assembly, and pipe-in-pipe-in-pipe assembly.
15. The pipe assembly according to claim 13, wherein the inner pipe is made of material capable of assisting in achieving near zero or negative coefficient of thermal expansion.
16. The pipe assembly according to claim 13, wherein the inner pipe is made of a material selected from the group consisting of: austenitic stainless steel, grade 304 stainless steel, and grade 316 stainless steel.
17. The pipe assembly according to claim 13, wherein the composite overwrap is bonded to the inner pipe utilizing residual stresses is accomplished by an autofrettage pressure cycle.
18. The pipe assembly according to claim 13, wherein the composite overwrap is made of a material selected from the group consisting of: graphite, carbon, and aramid.
The claims below are in addition to those above.
All refrences to claims which appear below refer to the numbering after this setence.
1. A method of controlling transmission power of signal transmitters and modulation and coding of transmitted signals in a multi-cell wireless communication system for increasing service capacity of a cell and decreasing inter-cell interference with nearby cells, the method comprising:
arranging a communication channel into multiple subchannels, wherein each subchannel consists of at least one subcarrier; and
adaptively controlling the modulation and coding of transmitted signals and signal transmission power, wherein the adaptive control is based on rules and constraints derived from system parameters and direct or indirect performance measurements, and wherein a selected transmission power level satisfies a Rise over Thermal (RoT) threshold requirement, and wherein the adaptive control comprises:
a first process wherein an achievable Channel Quality Information (Qnew) at the receiver is updated by:
Qnew=Qcurrent+Pmax\u2212Pcurrent, where Qcurrent denotes a recent measured CQI (Channel Quality Information) at a receiver, Pmax denotes a maximum transmission power available at a transmitter, and Pcurrent denotes a recent transmission power at the transmitter;
in a case where a primary criteria is to maximize throughput while controlling transmission power:
if Qnew exceeds CQI requirement for a highest MCS (modulation and coding scheme) in a protocol, the highest MCS is selected and Pnew is set as the transmission power level for that MCS with a certain margin;
if Qnew is lower than the CQI requirement for the highest MCS, the maximum transmission power (Pnew) is selected to derive a corresponding MCS based on the value of Qnew; and
if Qnew is lower than the CQI requirement for the lowest MCS in the protocol, transmission may be denied and outage process may start;
in a case where the primary criteria is to minimize transmission power while meeting a data rate requirement:
if Qnew exceeds the CQI requirement for a given MCS in the protocol, a necessary transmission power level is set for the given MCS with a certain margin; and
if Qnew is lower than the CQI requirement for the given or lowest MCS, transmission is denied; and
a second process wherein an RoT check is performed and, if needed, the power is adjusted to meet the RoT threshold, the second process comprising:
Rnew Rcurrent+Pnew\u2212Pcurrent, where Rnew denotes a new RoT resulting from the first process computations, and Rcurrent denotes an RoT measurement before application of Pnew, and wherein:
if Rnew is less than the RoT threshold, decisions made during the first process concerning the transmission power level and MCS are maintained; and
if Rnew exceeds the RoT threshold, the transmission power level is reduced to meet the RoT threshold requirement; and
a new transmission power level is calculated as:
Pnew=Pcurrent+Rthreshold\u2212Rcurrents
and a new achievable CQI is calculated as:
Qnew=Qcurrent+Rthreshold\u2212Rcurrent,
where Rthreshold denotes the RoT threshold and an appropriate MCS is selected based on Qnew.
2. The method of claim 1, wherein service capacity is the capacity to communicate data, voice, video, or any combination thereof.
3. The method of claim 1, wherein at an initial stage of network entry, a mobile station can estimate an uplink CQI and RoT based on an observed path-loss from a downlink message and choose an appropriate transmission power and MCS, and a certain margin to account for the estimation error.
4. In a multi-carrier, multi-cell wireless communication system, a process of controlling transmission power of signal transmitters and modulation and coding of transmitted signals, the process comprising:
configuring a communication channel into multiple subchannels, wherein each subchannel consists of at least one subcarrier; and
adaptively controlling modulation and coding of the transmitted signals and signal transmission power to substantially achieve a balance between maximizing a capacity of a serving cell and minimizing interference with other cells due to power emission from the serving cell, wherein the adaptive control is based on rules and constraints derived from system parameters and performance measurements.
5. The process of claim 4, wherein:
the process is applicable to downlink, uplink, or both;
the multi-carrier system comprises OFDM, or Multi-Carrier Code Division Multiple Access (MC-CDMA); and
a Time Division Duplexing (TDD) or a Frequency Division Duplexing (FDD) technique is employed.
6. The process of claim 4, wherein a total transmission power of a base station is controlled and a maximum allowable level is set relatively high for large cells, isolated cells, or cells with large frequency reuse factors, and wherein the total transmission power of the base station is set relatively low for small cells, congested cells, or cells with small frequency reuse factors, and wherein the total transmission power is adjusted either by changing a power density of each subcarriersubchannel or changing a number of utilized subcarrierssubchannels.
7. The process of claim 4, wherein a performance measurement is SINR (signal-to-interference-plus-noise ratio), BER (bit error rate), PER (packet error rate), or any combination thereof, and wherein the performance measurement is a single number or a statistical indicator.
8. The process of claim 4, wherein modulation and coding requirements are pre-stored in a table based on system simulation or measurement, or the quality requirements are dynamically adjusted.
9. The process of claim 4, wherein a selected transmission power level requires to satisfy a Rise over Thermal (RoT) threshold, and wherein:
a central control method is adapted and:
a network-wide coordination among adaptive controllers globally optimizes the RoT threshold to achieve high overall performance; and
a central processor, based on information from base stations, determines the RoT threshold with which the network capacity on a particular subchannel is optimized; or
a distributed method is adapted and:
the RoT threshold is computed for each data link; and
an RoT threshold Calculator resides within or outside of a controller, wherein inputs to the Calculator include one or more of the following factors: cell configuration, frequency reuse factor, geometrypath loss information, transmission priority, subchannel configuration, and feedback from other cells or other users and an output of the Calculator is the RoT threshold value.
10. In a multi-carrier, multi-cell communication system wherein a communication channel is configured into multiple subchannels and each subchannel includes multiple subcarriers, an apparatus for controlling transmission power and modulation and coding of transmitted signals, the apparatus comprising:
at least one controller configured to process input information and generate output signals for controlling transmission power, modulation and coding, or both, wherein the controller uses a part or all of the inputs to generate the output signals, and wherein the output signals are sent to and employed by the transmitter in a next transmission; and
wherein the input information to the controller comprises:
direct or indirect performance measurements, wherein the performance measurements are frequently varying and repeatedly updated; and
system parameters and requirements, wherein the system parameters are stable and infrequently updated.
11. The apparatus of claim 10, wherein the AMCP controller (a) selects a transmission power level that satisfies the Signal to Noise Ratio (SNR) or Rise over Thermal (RoT) threshold requirement and that achieves the highest modulation and coding scheme (MCS) for applications with adaptive MCS schemes, and (b) selects the corresponding MCS.
12. The apparatus of claim 10, wherein the SNR or RoT threshold is calculated using the cell configuration, frequency reuse factor, geometry and path-loss information, transmission priority, subchannel configuration, feedback from other cells, or any combination thereof; and wherein:
the SNR or RoT threshold is set relatively low if
the cell size is relatively small;
the configuration is relatively congested;
the frequency reuse factor is small;
the path-loss delta is relatively small; or
the transmission priority is low; and the SNR or RoT threshold is set relatively high if
the cell size is relatively large;
the configuration is relatively isolated;
the frequency reuse factor is large;
the path-loss delta is relatively large; or
the transmission priority is high.
13. The apparatus of claim 12, wherein a common SNR or RoT threshold is first set for all active links in one direction to control the interference with close-by cells, and wherein the common SNR or RoT threshold is used as a constraint in the calculation of individual SNR or RoT thresholds for each link.
14. The apparatus of claim 12, wherein information pertaining to interference occurrences within a network is used by the base station to compute the SNR or RoT threshold.
15. The apparatus of claim 10, wherein the path-loss for a mobile station to its serving andor adjacent base stations is determined from strength of downlink or uplink signals from and to the base station, wherein:
each base station sends a unique downlink preamble signal or a pilot pattern and the mobile station scans through these preamble signals or pilot patterns using correlation or other signal processing methods, and wherein a result of a correlation indicates the path-loss to each base station, and wherein the path-loss information is fed back by the mobile station to its serving base station; or
the mobile station sends a unique ranging signal to a target base station and from the strength of such uplink signals the base station, and other close-by base stations that also detect such uplink signal, measure the corresponding path-loss.
16. The apparatus of claim 10, wherein the inputs and outputs of the controller correspond to an individual subchannel in case each subchannel uses a modulation and coding and a power control different from those of other subchannels or correspond to a set of subchannels in case the set of subchannels use the same modulation and coding and power control to reduce the control overhead.
17. An apparatus for controlling transmission power of signal transmitters and modulation and coding of transmitted signals in a multi-cell wireless communication system for increasing service capacity of a cell and decreasing inter-cell interference with nearby cells, the apparatus comprising:
a means for arranging a communication channel into multiple subchannels, wherein each subchannel consists of at least one subcarrier;
a means for adaptively controlling the modulation and coding of the transmitted signals and the signal transmission power, wherein the adaptive control operation is based on rules and constraints derived from system parameters and direct or indirect performance measurements, and wherein the selected transmission power level satisfies a Rise over Thermal (RoT) threshold requirement; and
a means for calculating the RoT threshold, wherein the means for calculating calculates the RoT threshold by applying at least one of the following factors: cell configuration, frequency reuse factor, geometrypath loss information, transmission priority, subchannel configuration, and feedback from other cells or other mobile users.
18. A base station in a multi-cell wireless communication network capable of controlling transmission power and modulation and coding of transmitted signals, the base station comprising:
a transceiver;
a facility, coupled to the transceiver, for adaptively controlling the modulation and coding of transmitted signals and signal transmission power, wherein the adaptive control is based on boundaries derived from system specifics and direct or indirect performance indicators, and wherein the selected transmission power level satisfies a Rise over Thermal (RoT) or a Signal to Noise Ratio (SNR) threshold requirement;
a facility for calculating the RoT threshold based on cell configuration, frequency reuse factor, geometrypath loss information, transmission priority, subchannel configuration, feedback from other cells or other remote units, or any combination thereof;
a configuration where information pertaining to interference occurrences within the network is used by the base station to compute the RoT threshold; and
a configuration wherein the path-loss for a mobile station to the base stations is determined from strength of downlink or uplink signals from and to the base station.
19. The base station of claim 18, wherein the total transmission power of the base station is controlled and a maximum allowable level is set relatively high for large cells, isolated cells, or cells with large frequency reuse factors, and wherein the total transmission power of the base station is set relatively low for small cells, congested cells, or cells with small frequency reuse factors, and wherein the total transmission power is adjusted either by changing a power density of each subcarriersubchannel or changing a number of utilized subcarrierssubchannels.
20. The base station of claim 18, wherein the path-loss for a mobile station to the base stations is determined in the following manner:
each base station sends a unique downlink preamble signal or a pilot pattern and the mobile station scans through these preamble signals or pilot patterns using correlation or other signal processing methods, and wherein a result of a correlation indicates the path-loss to each base station, and wherein the path-loss information is fed back by the mobile station to its serving base station; or
the mobile station sends a unique ranging signal to the base station and from the strength of such uplink signals the base station, and other close-by base stations that also detect such uplink signal, measure the corresponding path-loss.