Method and system for power controlled effective allocation of sub-bands in ultra-wideband communication
First Claim
1. A method for power efficient channel allocation in a multi-band multi-user ultra-wideband (UWB) system, including a plurality of K users, a plurality of S sub-bands, and a plurality of N sub-carriers, wherein each kth of said plurality of K users requests transmission with a data transmission rate Rk, including the steps of:
- defining a sub-band assignment matrix A including a plurality of aks elements, wherein k=1, 2, . . . , k, and s=1, 2, . . . , S, said aks represents the duration of a data packet which the kth user is allowed to transmit on the sth sub-band;
establishing a power allocation matrix P including a plurality of Pks elements, each Pks representing the transmit power of the kth user at each sub-carrier of the sth sub-band;
calculating said sub-band assignment matrix A and said power allocation matrix P under pre-defined constraints to allocate the users'"'"' transmissions to respective sub-bands, thereby minimizing the overall transmit power in said UWB system; and
, adapting said sub-band assignment matrix A and said power allocation matrix P to said respective sub-bands'"'"' conditions, if said allocation of the users'"'"' transmissions to said respective sub-bands deviates from a predetermined allocation criteria.
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Abstract
A power controlled sub-band assignment and power allocation among users in a multiband UWB system aims to reduce power consumption without compromising performance. The overall transmit power is minimized under the practical constraints, including packet error rate, transmission rate, and FCC regulations. To insure the system feasibility in variable channel conditions, an optimization scheme manages the assignment of UWB devices to respective channels subject to their suitability to the requested users'"'"' transmission rates. An inexpensive suboptimal approach reduces the complexity of the optimization procedure and achieves a comparable performance to those of the complex full search optimization routine. The suboptimal scheme obtains the feasible solutions adaptively when the channels assignment, initially calculated under the optimization criteria, is not feasible for the user'"'"'s rate requirement.
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Citations
20 Claims
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1. A method for power efficient channel allocation in a multi-band multi-user ultra-wideband (UWB) system, including a plurality of K users, a plurality of S sub-bands, and a plurality of N sub-carriers, wherein each kth of said plurality of K users requests transmission with a data transmission rate Rk, including the steps of:
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defining a sub-band assignment matrix A including a plurality of aks elements, wherein k=1, 2, . . . , k, and s=1, 2, . . . , S, said aks represents the duration of a data packet which the kth user is allowed to transmit on the sth sub-band;
establishing a power allocation matrix P including a plurality of Pks elements, each Pks representing the transmit power of the kth user at each sub-carrier of the sth sub-band;
calculating said sub-band assignment matrix A and said power allocation matrix P under pre-defined constraints to allocate the users'"'"' transmissions to respective sub-bands, thereby minimizing the overall transmit power in said UWB system; and
,adapting said sub-band assignment matrix A and said power allocation matrix P to said respective sub-bands'"'"' conditions, if said allocation of the users'"'"' transmissions to said respective sub-bands deviates from a predetermined allocation criteria. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for power controlled optimization of channel allocation in multi-band multi-user ultra-wideband (UWB) system for transmitting packets from a plurality of K users at a plurality of S sub-bands using a plurality of N sub-carriers, each kth user requesting a data transmission rate Rk, the method comprising the steps of:
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(a) defining a sub-band assignment matrix A, including a plurality of aks elements, wherein k=1, 2, . . . , K, and s=1, 2, . . . , S, and wherein each said aks element represents the duration of a data packet which a kth user of said plurality of K users is allowed to transmit on the Sth sub-band of said plurality of S sub-bands, (b) setting A=0K×
S,(c) defining user optimization list Klive={1, 2, . . . , K};
(d) defining sub-band optimization list Slive={1, 2, . . . , S};
(e) calculating a dummy overall transmission power Pdummyk for each kth user of said plurality of k users, wherein Pdummyk=min Σ
s−
1SaksPks, sε
Slive;
(f) assigning said respective sub-band to a user k with the highest Pdummyk, and removing said user k from said user optimization list Klive;
(g) removing said assigned respective sub-band from said sub-band optimization list Slive;
(h) repeating said steps (e)-(g) for the remaining users in said user optimization list Klive, until said Klive=0, thus assigning transmissions of said plurality of K users to the said plurality of S sub-bands in said sub-band optimization list Slive; and
(i) comparing a transmit power for each assigned sub-band to a pre-determined maximum power value. - View Dependent Claims (17, 18, 19)
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20. A multi-user multi-band ultra-wide band (UWB) system with an efficient sub-band assignment and power allocation, the UWB system transmitting data packets from a plurality of K users at a plurality of S sub-bands using a plurality of N sub-carriers using Orthogonal Frequency Division Multiplexing (OFDM), the system comprising:
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a sub-band assignment matrix A, including a plurality of aks elements, wherein k=1, 2, . . . , K, and S=1, 2, . . . , S, and wherein each said aks element represents the duration of a data packet which a kth user of said plurality of K users is allowed to transmit on the Sth sub-band and said plurality of S sub-bands, a user optimization list Klive={1, 2, . . . , K};
a sub-band optimization list Slive={1, 2, . . . , S}; and
a processor unit adapted for;
(a) iterative calculation of a dummy overall transmission power Pdummyk for each kth user of said plurality of k users wherein Pdummyk=min Σ
s−
1SaksPks, s ε
Slive;
(b) assignment of said sth sub-band to a user k with the highest Pdummyk, and removal of said user k from said user optimization list Klive;
(c) removal of said assigned respective sub-band from said sub-band optimization list Slive;
(d) repetition of said steps (a)-(c) for remaining users in said user optimization list Klive, until said Klive=0, thus assigning transmissions of said plurality of the K users to said plurality of S sub-bands in said sub-band optimization list Slive; and
(e) comparison of a transmit power for each assigned sub-band to a pre-determined maximum power value;
said processor unit indicating an outage if the transmission power for said each assigned sub-band is larger than said pre-determined maximum power value or if Slive=0 and Klive≠
0; and
reducing said requested data transmission rate Rk for a chosen at least one user of said plurality of K users.
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Specification