1. A process for quenching an alkaline catalyst used in a melt polycondensation reaction for the production of polycarbonate, the process comprising:
combining an intermediate polycarbonate composition with a quenching;
composition in a reactor, wherein the quenching composition includes a compound having at least one acid or acid ester moiety and at least one amine moiety;
heating the intermediate polycarbonate; and
reducing the pressure in the reactor to produce a finished polycarbonate.
2. The process according to claim 1, wherein the quenching composition includes a compound of formula:
RaRbNASO3Rc
wherein Ra, and Rb are each independently hydrogen, C1-C12 alkyl, C1-C12 aryl, or C1-C18 alkylaryl; Ra, Rb, singly or in combination form a heterocyclic ring structure with N; Rc is a hydrogen; and A is C1-C12 alkyl, C1-C12 aryl, or C1-C18 alkylaryl.
3. The process according to claim 1, wherein the quenching composition includes a compound of formula:
RaRbRcNASO3
wherein Ra and Rb are each independently hydrogen, C1-C12 alkyl, C1-C12 aryl, or C1-C18 alkylaryl; Rc is a hydrogen; Ra, Rb, singly or in combination form a heterocylic ring structure with N; and A is C1-C12 alkyl, C1-C12 aryl, or C1-C18 alkylaryl.
4. The process according to claim 1, wherein the quenching composition comprises N-(2-hydroxyethyl)piperazine-N-3-propanesulfonic acid compound.
5. The process according to claim 1, wherein the quenching composition comprises 1,4,-piperazinebis(ethanesulfonic acid).
6. The process according to claim 1, wherein the quenching composition comprises 5-dimethylamino-1-napthalenesulfonic acid.
7. The process according to claim 4, wherein about 15 equivalents of the quencher compound per alkaline catalyst is added to quench the residual catalyst.
8. The process according to claim 5, wherein about two equivalents of the quencher compound per alkaline catalyst is added to quench the residual catalyst.
9. The process according to claim 6, wherein about two equivalents of the quencher compound per alkaline catalyst is added to quench the residual catalyst.
10. The process according to claim 1, wherein heating and reducing the pressure in the reactor are at a temperature and a pressure effective for removing low molecular weight oligomers, byproduct phenol and unreacted monomers from the intermediate polycarbonate.
11. The process according to claim 1, wherein heating the intermediate polycarbonate comprises increasing the temperature to an amount greater than 260 C.
12. The process according to claim 1, wherein heating the intermediate polycarbonate comprises increasing a temperature to greater than 260 C.
13. The process according to claim 1, wherein reducing the pressure comprises stepwise reducing the pressure to less than about 0.8 torr.
14. A polycarbonate article manufactured in accordance with the process of claim 1, wherein the polycarbonate is substantially a linear polycarbonate comprising less than 1500 ppm of a branched polycarbonate structure.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for determining attributes of communication channels of multi-user (MU)-multiple input multiple output (MIMO) users in an orthogonal frequency division multiplexing based multiple access (OFDMA) system, the method comprising:
receiving from a base station, for at least one sub-band of contiguous sub-carriers, an indication of an estimate of or an upper-bound on a total number of streams that are co-scheduled by the base station on the at least one sub-band or an indication of a fraction (\u03b1) of a transmit power at the base station that is applied to streams that are scheduled for transmission to a particular user;
determining one or more signal quality measures for the at least one sub-band based on at least one of the fraction or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band; and
transmitting to the base station an indication of the one or more signal quality measures.
2. The method of claim 1, wherein the signal quality measures are signal-to-interference-plus-noise ratios (SINRs), the indication of the one or more signal quality measures is an indication of one or more channel quality indices (CQIs) that are based on the SINRs, and wherein the method further comprises:
determining a precoder matrix for the at least one sub-band based on at least one of the fraction or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band, wherein the transmitting further comprises transmitting to the base station an indication of the precoder matrix.
3. The method of claim 2, wherein the receiving further comprises receiving an indication of a suggested or an upper-bound precoder rank and wherein the determining one or more signal quality measures and the determining the precoder matrix is further based upon at least one of the fraction, the suggested or upper-bound precoder rank, or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band.
4. The method of claim 3, wherein at least one of the precoder matrix or the one or more SINRs are determined under the assumption that a remaining fraction of the transmit power is 1\u2212\u03b1 and is assigned to streams that are scheduled for transmission to users co-scheduled with the particular user.
5. The method of claim 4, wherein at least one of the precoder matrix or the one or more SINRs are determined under the assumption that the streams that are scheduled for transmission to the particular user are allocated equal power and that the streams that are scheduled for transmission to the users co-scheduled with the particular user are allocated equal power.
6. The method of claim 3, wherein the precoder matrix is determined in accordance with at least one of single-user scheduling rules or multi-user scheduling rules, wherein the one or more signal quality measures are determined in accordance with at least one of the single-user scheduling rules or the multi-user scheduling rules and wherein the transmitting further comprises transmitting at least one tag identifying each signal quality measure as being determined in accordance with the single-user scheduling rules or the multi-user scheduling rules and at least one other tag identifying the precoder matrix as being determined in accordance with the single-user scheduling rules or the multi-user scheduling rules.
7. The method of claim 6, wherein the precoder matrix and the one or more SINRs are determined under the multi-user scheduling rules.
8. The method of claim 7, wherein the determining one or more signal quality measures further comprises determining one or more other signal quality measures in accordance with the single-user scheduling rules based on the precoder matrix and wherein the transmitting further comprises transmitting an indication of the one or more other signal quality measures.
9. The method of claim 6, wherein the precoder matrix and the one or more SINRs are determined under the single-user scheduling rules, wherein the method further comprises determining one or more other signal quality measures in accordance with the multi-user scheduling rules based on the precoder matrix and wherein the transmitting further comprises transmitting an indication of the one or more other signal quality measures.
10. The method of claim 9, wherein the precoder matrix is a first precoder matrix, wherein the method further comprises determining a second precoder matrix based on the first precoder matrix in accordance with the multi-user scheduling rules and wherein the transmitting further comprises transmitting an indication of the second precoder matrix to the base station.
11. The method of claim 9, wherein the determining the first precoder matrix comprises determining an other rank as the rank for the first precoder matrix, wherein the determining the second precoder matrix comprises selecting the minimum rank between the received rank and the other rank as the rank for the second precoder matrix and wherein the transmitting further comprises transmitting an indication of the other rank to the base station.
12. The method of claim 11, wherein the determining the second precoder matrix comprises determining a sub-matrix of the first precoder matrix as the second precoder matrix.
13. A method for determining precoders for communication channels of multi-user (MU)-multiple input multiple output (MIMO) users in an orthogonal frequency division multiplexing based multiple access (OFDMA) system, the method comprising:
receiving from a base station, for at least one sub-band of contiguous sub-carriers, an indication of an estimate of or an upper-bound on a total number of streams that are co-scheduled by the base station on the at least one sub-band and an indication of a fraction (\u03b1) of a transmit power at the base station that is applied to streams that are scheduled for transmission to a particular user;
determining a precoder matrix for the at least one sub-band based on at least one of the fraction or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band; and
transmitting to the base station an indication of the precoder matrix.
14. The method of claim 13, wherein the method further comprises
determining one or more signal quality measures for the at-least one sub-band based on at least one of the fraction or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band, wherein the transmitting further comprises transmitting to the base station an indication of the one or more signal quality measures.
15. The method of claim 14, wherein the signal quality measures are signal-to-interference-plus-noise ratios (SINRs), the indication of the one or more signal quality measures is an indication of one or more channel quality indices (CQIs) that are based on the SINRs.
16. The method of claim 14, wherein the receiving further comprises receiving an indication of a suggested or an upper-bound precoder rank and wherein the determining one or more signal quality measures and the determining the precoder matrix is further based upon at least one of the fraction, the suggested or upper-bound precoder rank, or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band.
17. The method of claim 16, wherein at least one of the precoder matrix or the one or more signal quality measures are determined under the assumption that a remaining fraction of the transmit power is 1\u2212\u03b1 and is assigned to streams that are scheduled for transmission to users co-scheduled with the particular user.
18. The method of claim 17, wherein at least one of the precoder matrix or the one or more SINRs are determined under the assumption that the streams that are scheduled for transmission to the particular user are allocated equal power and that the streams that are scheduled for transmission to the users co-scheduled with the particular user are allocated equal power.
19. The method of claim 18, wherein the precoder matrix is determined in accordance with at least one of single-user scheduling rules or multi-user scheduling rules, wherein the one or more signal quality measures are determined in accordance with at least one of the single-user scheduling rules or the multi-user scheduling rules and wherein the transmitting further comprises transmitting at least one tag identifying each signal quality measure as being determined in accordance with the single-user scheduling rules or the multi-user scheduling rules and at least other one tag identifying the precoder matrix as being determined in accordance with the single-user scheduling rules or the multi-user scheduling rules.
20. A receiver system for determining attributes of communication channels of multi-user (MU)-multiple input multiple output (MIMO) users in an orthogonal frequency division multiplexing based multiple access (OFDMA) system comprising:
a receiver configured to receive from a base station, for at least one sub-band of contiguous sub-carriers, an indication of an estimate of or an upper-bound on a total number of streams that are co-scheduled by the base station on the at least one sub-band or an indication of a fraction of a transmit power at the base station that is applied to streams that are scheduled for transmission to a particular user;
a processor configured to determine one or more signal quality measures for the at least one sub-band based on at least one of the fraction or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band; and
a transmitter configured to transmit to the base station an indication of the one or more signal quality measures.