iber has to wait very long for a turn. "The usual techniques employed to suppress interference use adaptive spatial filters, which require expensive RF components and a large number of computations to queue the subscribers' signals," says Kavehrad. "However, with our approach, we need only a simple, cost-effective spatial filter and relatively fewer computations. Our simulations show that the performance of the new approach and the traditional technique are comparable. Thus, our strategy shows a practical compromise between complexity and cost, while achieving the desired signal quality." INTERFERENCE 6.11.2 Quieter Ovens As just about anyone who has ever used a wireless phone or WLAN can attest, wireless ovens are almost as good at creating electrical interference as they are at heating up TV dinners. Researchers at the University of Michigan College of Engineering pondered this problem and have developed an ele- gantly simple technique that dramatically reduces the interference microwave ovens create in telephones and wireless computer networks. Worldwide, there are hundreds of millions of microwave ovens in kitchens, offices, and laboratories, each with a magnetron that creates communications problems ranging from an aggravating crackle during a friendly telephone call, to the disruption of 911 calls and the flow of data in wireless computer net- works. Although these effects are difficult to quantify, it's safe to say they're an annoyance, an economic drain, and potentially life-threatening. The basic difficulty is that microwave ovens operate at a frequency near 2.45GHz-about the same frequency at which telephones and wireless com- puters operate. In the microwave oven, there are two magnets, one at each end of the magnetron. In an amazingly simple discovery, University of Michigan College of Engineering Professor Ronald Gilgenbach and a research team composed of Professor Y. Y. Lau and graduate student, Bogdan Neculaes, all from the department of Nuclear Engineering and Radiological Sciences, found that whe